CLINICAL STUDIES ON THE FOLLOWING INGREDIENTS:
Ginkgoxine (Ginkgo Biloba as 24% extract)
A Placebo-Controlled, Double-blind, Randomized Trial of an Extract of Ginkgo Biloba for Dementia
Context. —EGb 761 is a particular extract of Ginkgo biloba used in Europe to alleviate symptoms associated with numerous cognitive disorders. Its use in dementias is based on positive results from only a few controlled clinical trials, most of which did not include standard assessments of cognition and behavior.
Objective. —To assess the efficacy and safety of EGb in Alzheimer disease and multi-infarct dementia.
Design. —A 52-week, randomized double-blind, placebo-controlled, parallelgroup, multicenter study.
Patients. —Mildly to severely demented outpatients with Alzheimer disease or multi-infarct dementia, without other significant medical conditions.
Intervention. —Patients assigned randomly to treatment with EGb (120 mg/d) or placebo. Safety, compliance, and drug dispensation were monitored every 3 months with complete outcome evaluation at 12, 26, and 52 weeks.
Primary Outcome Measures. —Alzheimer’s Disease Assessment Scale—Cognitive subscale (ADAS-Cog), Geriatric Evaluation by Relative’s Rating Instrument (GERRI), and Clinical Global Impression of Change (CGIC).
Results. —From 309 patients included in an intent-to-treat analysis, 202 provided evaluable data for the 52-week end point analysis. In the intent-to-treat analysis, the EGb group had an ADAS-Cog score 1.4 points betterthan the placebo group (P=.04) and a GERRI score 0.14 points better than the placebo group (P=.004). The same patterns were observed with the evaluable data set in which 27% of patients treated with EGb achieved at least a 4-point improvement on the ADAS-Cog, compared with 14% taking placebo (P=.005); on the GERRI, 37% were considered improved with EGb, compared with 23% taking placebo (P=.003). No difference was seen in the CGIC. Regarding the safety profile of EGb, no significant differences compared with placebo were observed in the number of patients reporting adverse events or in the incidence and severity of these events.
Conclusions. —EGb was safe and appears capable of stabilizing and, in a substantial number of cases, improving the cognitive performance and the social functioning of demented patients for 6 months to 1 year. Although modest, the changes induced by EGb were objectively measured by the ADAS-Cog and were of sufficient magnitude to be recognized by the caregivers in the GERRI.
Reference: Le Bars, Pierre L., et al. “A placebo-controlled, double-blind, randomized trial of an extract of Ginkgo biloba for dementia.” Jama 278.16 (1997): 1327-1332.
The Efficacy of Ginkgo biloba on Cognitive Function in Alzheimer Disease
Conclusions Based on a quantitative analysis of the literature there is a small but significant effect of 3- to 6-month treatment with 120 to 240 mg of G biloba extract on objective measures of cognitive function in AD. The drug has not had significant adverse effects in formal clinical trials but there are 2 case reports of bleeding complications. In AD, there are limited and inconsistent data that preclude determining if there are effects on noncognitive behavioral and functional measures as well as on clinician’s global rating scales. Further research in the area will need to determine if there are functional improvements and to determine the best dosage. Additional research will be needed to define which ingredients in the ginkgo extract are producing its effect in individuals with AD.
GINKGO BILOBA is a living fossil tree having undergone little evolutionary change over almost 200 million years. While currently it is essentially extinct in the wild, it is widely cultivated for its nut as well as for its leaves. The tree has a high tolerance to urban and industrial pollution and is extremely resistant to insects, bacteria, viruses, and fungi. Extracts of the leaves have been used for 5000 years in traditional Chinese medicine for various purposes. Medicinal extracts are made from dried leaves. Studies on the biological activity of different components of the ginkgo leaf began with modern scientific methods about 20 years ago.
Currently, ginkgo extracts used for medicinal purposes are usually standardized to contain 24% ginkgo-flavone glycosides and 6% terpenoids. The terpenoids include bilobalide and the ginkgolides A, B, C, M, and J that are 20-carbon cage molecules with six 5-membered rings. The ginkgolides are antagonists of platelet-activating factor (PAF) that has numerous biological effects.1 Besides causing platelet activation and aggregation, PAF produces proinflammatory effects (eg, increasing vascular permeability), is an extremely potent ulcerogen in the stomach, and contracts smooth muscle, including bronchial muscle. Platelet-activating factor has a direct effect on neuronal function and long-term potentiation.2,3 An initial report4 suggested that lissencephaly, a disorder of neural migration and dendritic branching, was associated with changes in the gene coding a PAF inactivating enzyme found in cerebral cortex, PAF acetylhydrolase. This was not confirmed in a later independent laboratory study.5
The other major components of ginkgo extract are the flavonoids that contribute to ginkgo’s antioxidant and free radical scavenger effects.6 Ginkgo has been found to (1) reduce cell membrane lipid peroxidation in experimental spinal cord injury similarly to methylprednisolone7; (2) reduce bromethalin-induced cerebral lipid peroxidation and edema8; (3) protect brain neurons against oxidative stress induced by peroxidation9- 11; (4) decrease neuronal injury following ischemia or electroconvulsive shock12; and (5) reduce subchronic cold stress effects on receptor desensitization.13
Other biological effects of G biloba extract have been observed. It is an inhibitor of monoamine oxidase A and B.14 Biological effects in various mammalian species have been demonstrated in many organs, such as decreasing retinal neovascularization following injury,15 altering the immune system16 and promoting compensation from vestibular deafferentation.17
Therapeutically, ginkgo may be biologically plausible to use in Alzheimer disease (AD) for several reasons. While the cause and underlying pathophysiological features of AD are unknown, prominent hypotheses as to the cause center around age-related oxidative injury.18,19 As described earlier, the flavonoid components of ginkgo appear to be useful in animal models in preventing some types of oxidative and peroxidative neuronal injury. Another hypothesis of a cause of AD centers around an inflammatory process.20,21 Ginkgo being a PAF antagonist has anti-inflammatory effects. Another reason for the plausibility of use of ginkgo in individuals with AD also relates to its activity as a PAF antagonist. The effect of PAF antagonism directly on brain function is fairly unexplored. 2,3
Ginkgo has been widely used by naturopathic doctors and other alternative and complementary health care providers. Alternative or complementary medicine is widely used in North America with 34% of US adults interviewed in 1990 having used some form of alternative medicine in the past year.22 In the United States people spend an estimated $1.5 billion per year on herbal medicines with projected annual growth of 15%.23 Germany is one of the largest herbal users among American or western European countries with total sales in 1993 of $1.9 billion for plant-based allopathic medicines (half of these prescribed by physicians) and with 5 million prescriptions for ginkgo in 1988. Clinically, ginkgo extract is widely used in Europe for treatment of memory disorders associated with aging, including AD and vascular dementia. It is already widely used in the United States as an alternative therapy for AD despite the presence of only 1 American study.24 Prior to the publication of that American trial, a conservative estimate at a university cognitive assessment clinic found 10% of patients using alternative medicines to improve cognitive function and an additional 29% to improve general health.25 A less conservative estimate comes from another study26 that found 55% of caregivers had used at least 1 alternative medicine to improve the patient’s memory. Ginkgo was the major alternative treatment besides vitamins in those studies.
To help define the efficacy of G biloba in AD, a review of the current literature and a meta-analysis of studies that met minimally acceptable scientific criteria was performed.
Reference: Oken, Barry S., Daniel M. Storzbach, and Jeffrey A. Kaye. “The efficacy of Ginkgo biloba on cognitive function in Alzheimer disease.” Archives of neurology 55.11 (1998): 1409-1415. doi:10.1001/archneur.55.11.1409.
Ginkgo Biloba Extract Neuroprotective Action Is Dependent on Heme Oxygenase 1 in Ischemic Reperfusion Brain Injury
Background and Purpose— Ginkgo biloba extracts are now prescribed in several countries for their reported health benefits, particularly for medicinal properties in the brain. The standardized Ginkgo extract, EGb761, has been reported to protect neurons against oxidative stress, but the underlying mechanisms are not fully understood.
Methods— To characterize the oral consumption of EGb761 in transient ischemia, we performed the middle cerebral artery occlusion (MCAO) filament model in wild-type and heme oxygenase 1 (HO-1) knockouts. Mice were pretreated for 7 days before the transient occlusion or posttreated acutely during reperfusion; then neurobehavioral scores and infarct volumes were assessed. Furthermore, primary cortical neuronal cultures were used to investigate the contribution of the antioxidant enzyme HO-1 in the EGb761-associated cytoprotection.
Results— Mice that were pretreated with EGb761 had 50.9±5.6% less neurological dysfunction and 48.2±5.3% smaller infarct volumes than vehicle-treated mice; this effect was abolished in HO-1 knockouts. In addition to the prophylactic properties of EGb761, acute posttreatment 5 minutes and 4.5 hours after reperfusion also led to significant reduction in infarct size (P<0.01). After our previous demonstration that EGb761 significantly induced HO-1 levels in a dose- and time-dependent manner in neuronal cultures, here we revealed that this de novo HO-1 induction was required for neuroprotection against free radical damage and excitotoxicity as it was significantly attenuated by the enzyme inhibitor.
Conclusion— These results demonstrate that EGb761 could be used as a preventive or therapeutic agent in cerebral ischemia and suggest that HO-1 contributes, at least in part, to EGb761 neuroprotection.
Reference: Saleem, Sofiyan, et al. “Ginkgo biloba extract neuroprotective action is dependent on heme oxygenase 1 in ischemic reperfusion brain injury.”Stroke 39.12 (2008): 3389-3396.
The effects of melatonin and Ginkgo biloba extract on memory loss and choline acetyltransferase activities in the brain of rats infused intracerebroventricularly with β-amyloid 1–40
Intraventricular infusion of rats with β-amyloid for 14 days resulted in memory deficit in the water maze as well as decreases in choline acetyltransferase activities and somatostatin levels in the cerebral cortex and hippocampus. These changes were not altered by daily intraperitoneal injection of 20 mg/Kg melatonin. Orally administered Ginkgo biloba extract, however, partially reversed the memory deficit and the decrease in choline actyltransferase activities in the hippocampus. The latter treatment failed to reverse the decrease in somatostatin levels. The results indicate that orally administered Ginkgo biloba extract can protect the brain against β-amyloid from changes leading to memory deficit through its effect on the cholinergic system.
Reference: Tang, F., et al. “The effects of melatonin and Ginkgo biloba extract on memory loss and choline acetyltransferase activities in the brain of rats infused intracerebroventricularly with β-amyloid 1–40.” Life sciences 71.22 (2002): 2625-2631.
Ginkgo biloba prevents mobile phone-induced oxidative stress in rat brain
Background: The widespread use of mobile phones (MP) in recent years has raised the research activities in many countries to determine the consequences of exposure to the low-intensity electromagnetic radiation (EMR) of mobile phones. Since several experimental studies suggest a role of reactive oxygen species (ROS) in EMR-induced oxidative damage in tissues, in this study, we investigated the effect of Ginkgo biloba (Gb) on MP-induced oxidative damage in brain tissue of rats. Methods: Rats (EMR+) were exposed to 900 MHz EMR from MP for 7 days (1 h/day). In the EMR+Gb groups, rats were exposed to EMR and pretreated with Gb. Control and Gb-administrated groups were produced by turning off the mobile phone while the animals were in the same exposure conditions. Subsequently, oxidative stress markers and pathological changes in brain tissue were examined for each groups. Results: Oxidative damage was evident by the: (i) increase in malondialdehyde (MDA) and nitric oxide (NO) levels in brain tissue, (ii) decrease in brain superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and (iii) increase in brain xanthine oxidase (XO) and adenosine deaminase (ADA) activities. These alterations were prevented by Gb treatment. Furthermore, Gb prevented the MP-induced cellular injury in brain tissue histopathologically. Conclusion: Reactive oxygen species may play a role in the mechanism that has been proposed to explain the biological side effects of MP, and Gb prevents the MP-induced oxidative stress to preserve antioxidant enzymes activity in brain tissue.
Refrence: Ilhan, Atilla, et al. “Ginkgo biloba prevents mobile phone-induced oxidative stress in rat brain.” Clinica Chimica Acta 340.1 (2004): 153-162.doi:10.1016/j.cccn.2003.10.012
Ginkgo biloba extract protects brain neurons against oxidative stress induced by hydrogen peroxide
Effect of Ginkgo biloba extract was examined on dissociated rat cerebellar neurons suffering from oxidative stress induced by hydrogen peroxide using a flow cytometer and ethidium bromide. Hydrogen peroxide at a concentration of 3 mM increased the number of neurons stained with ethidium (presumably dead neurons) in a time-dependent manner. Pretreatment of neurons with G. biloba extract (10 μg/ml greatly delayed a time-dependent increase in number of dead neurons during exposure to hydrogen peroxide. It was true, but less effective, in the case of treatment with G. biloba extract immediately or 60 min after start of oxidative stress. Results implicate G. biloba extract as a potential agent in protecting the neurons suffering from oxidative stress induced by hydrogen peroxide.
Refrence: Oyama, Yasuo, et al. “Ginkgo biloba extract protects brain neurons against oxidative stress induced by hydrogen peroxide.” Brain research 712.2 (1996): 349-352.doi:10.1016/0006-8993(95)01440-3
Effects of an extract of Gingko biloba on bromethalin-induced cerebral lipid peroxidation and edema in rats.
Highlight Terms Highlight biological terms.
Diseases(4) Genes/Proteins(2) Species(4) Chemicals(8)
The effects of administration of a commercially available extract of Gingko biloba (EGB) on bromethalin-induced brain lipid peroxidation and cerebral edema in adult male Sprague-Dawley rats was determined. Gingko biloba extract was given (100 mg/kg) by gavage immediately after bromethalin (1.0 mg/kg) administration. Rats were euthanatized at 24 hours after dosing. Brain lipid peroxidation was determined by measurement of brain malonaldehyde-thiobarbituric acid chromophore (MDA-TBA) concentration, brain sodium concentration, and brain water content. Treatment of bromethalin-dosed rats (10/group) with EGB was associated with a statistically significant (P less than 0.05) decrease in clinical sign severity, compared with bromethalin-dosed saline solution-treated rats. All rats given bromethalin and saline solution developed clinical signs of toxicosis including CNS depression, hind limb weakness, ataxia, paralysis, and coma. Some rats given bromethalin and EGB developed clinical signs, however, none developed hind limb paralysis. The brain MDA-TBA concentration (2.4 +/- 0.5 delta MDA-TBA concentration/mg of protein), percentage of water in brain tissue (80.3 +/- 0.30%), and brain sodium concentration (6.68 +/- 0.21 mg/g of dry weight) were significantly increased in rats given bromethalin and saline solution, compared with control rats given saline solution (1.0 +/- 0.1 delta MDA-TBA concentration/mg of protein; 78.1 +/- 0.33% water in brain tissue; 4.83 +/- 0.30 mg of brain Na+/g of dry weight) and rats given bromethalin and EGB (1.6 +/- 0.2 delta MDA-TBA concentration/mg of protein; 79.3 +/- 0.31% water in brain tissue; 5.37 +/- 0.34 mg of brain Na+/g of dry weight).(ABSTRACT TRUNCATED AT 250 WORDS).
Reference: Dorman, David C., L. M. Cote, and W. B. Buck. “Effects of an extract of Gingko biloba on bromethalin-induced cerebral lipid peroxidation and edema in rats.” American journal of veterinary research 53.1 (1992): 138-142.
Ginkgo biloba extract (EGb 761) independently improves changes in passive avoidance learning and brain membrane fluidity in the aging mouse.
Decreases in cell membrane fluidity may be a major mechanism of age-related functional decline. A prime cause for the decline of membrane fluidity may be the presence of free radicals. Gingko biloba extract EGb 761 protects neuronal cell membranes from free radical damage in vitro. Further, EGb 761 has repeatedly been shown to improve cognitive functions in man and in laboratory animals. To test if there is a link between these two actions we assessed the effects of EGb 761 on passive avoidance learning and on neuronal membrane fluidity in vivo in young (three-month-old), middle-aged (12-month-old) and aged (22 to 24-month-old) female NMRI mice. The animals were treated daily with 100 mg/kg EGb 761 for three weeks. There was a significant improvement in short-term memory, measured by the avoidance latency 60 seconds after the aversive stimulus (p < 0.0311), and of membrane fluidity (p < 0.01) in the aged animals, but no improvement in long-term memory as measured by the avoidance latency 24 hours after shock. However, no significant correlation between membrane fluidity and short-term memory performance was found. Taken together, these results indicate that EGb 761 independently improves changes in passive avoidance learning and brain membrane fluidity.
Refrence: Stoll, S., et al. “Ginkgo biloba extract (EGb 761) independently improves changes in passive avoidance learning and brain membrane fluidity in the aging mouse.” Pharmacopsychiatry 29.4 (1996): 144-149.
Myricetin and quercetin, the flavonoid constituents ofGinkgo biloba extract, greatly reduce oxidative metabolism in both resting and Ca2+-loaded brain neurons
The antioxidant action of myricetin and quercetin, the flavonoid constituents of the extract ofGinkgo biloba (EGb), on oxidative metabolism of brain neurons dissociated from the rats was examined using 2′,7′-dichlorofluorescin (DCFH) which is retained within the neurons nd then oxidized by cellular hydrogen peroxide to be highly fluorescent. Incubation with myricetin or quercetin reduced the oxidation of DCFH in resting brain neurons, more profoundly than EGb. Myricetin decreased the oxidative metabolism at concentrations of 3 nM or more. It was 10 nM or more for the case of quercetin. Incubation with each flavonoid constituent also reduced the Ca2+-induced increase in the oxidative metabolism without affecting the cellular content of DCFH or the intracellular concentrations of Ca2+. Such an antioxidant action of myricetin or quercetin may be responsible for a part of the beneficial effects of EGb on brain neurons suject to ischemia.
Reference: Oyama, Yasuo, et al. “Myricetin and quercetin, the flavonoid constituents ofGinkgo biloba extract, greatly reduce oxidative metabolism in both resting and Ca2+-loaded brain neurons.” Brain research 635.1-2 (1994): 125-129.
The neuroprotective properties of the Ginkgo biloba leaf: a review of the possible relationship to platelet-activating factor (PAF)
Ginkgo biloba (Ginkgoaceae) is an ancient Chinese tree which has been cultivated and held sacred for its health-promoting properties. There is substantial experimental evidence to support the view that Ginkgo biloba extracts have neuroprotective properties under conditions such as hypoxia/ischemia, seizure activity and peripheral nerve damage. Research on the biochemical effects of Ginkgo biloba extracts is still at a very early stage. One of the components of Ginkgo biloba, ginkgolide B, is a potent platelet-activating factor (PAF) antagonist. Although the terpene fraction of Ginkgo biloba, which contains the ginkgolides, may contribute to the neuroprotective properties of the Ginkgo biloba leaf, it is also likely that the flavonoid fraction, containing free radical scavengers, is important in this respect. Taken together, the evidence suggests that Ginkgo biloba extracts are worthy of further investigation as potential neuroprotectant agents.
Reference: Smith, Paul F., Karyn Maclennan, and Cynthia L. Darlington. “The neuroprotective properties of the Ginkgo biloba leaf: a review of the possible relationship to platelet-activating factor (PAF).” Journal of ethnopharmacology 50.3 (1996): 131-139. doi:10.1016/0378-8741(96)01379-7
Neuroprotective effects of Ginkgo biloba extract in brain ischemia are mediated by inhibition of nitric oxide synthesis
We studied the effects of pre-treatment (15 days) with oral administration of Ginkgo biloba extract (Ph-Gb 37,5–150 mg/kg) on brain malonildialdehyde (MDA), brain edema, brain nitrite and nitrate and delayed neuronal death following transient cerebral ischemia in the Mongolian gerbil. Survival was not modified, however, pre-treatment with Ginkgo biloba significantly and in a dose-dependent way reduced post-ischemic brain MDA levels and post-ischemic brain edema. Delayed neuronal death in the CA1 of the hippocampus was attenuated by the highest dose of the extract. Increase of nitrite and nitrate was observed after cerebral ischemia in the hippocampus and it was dose-dependently reduced in animals pretreated with Ph-Gb, thus suggesting that neuroprotective effects of Ginkgo biloba may be due to an inhibitory action on nitric oxide formation.
Gioacchino Calapaia, , , Anna Crupib, Fabio Firenzuolic, Maria C. Marcianoa, Francesco Squadritoa, Giuseppina Inferreraa, Alessandra Parisia, Antonio Rizzod, Costantino
Reference: Smith, Paul F., Karyn Maclennan, and Cynthia L. Darlington. “The neuroprotective properties of the Ginkgo biloba leaf: a review of the possible relationship to platelet-activating factor (PAF).” Journal of ethnopharmacology 50.3 (1996): 131-139.
Lipid peroxide, phospholipids, glutathione levels and superoxide dismutase activity in rat brain after ischaemia: Effect of ginkgo biloba extract
The influence of ginkgo biloba extract on the lipid peroxide product (malondialdehyde, MDA), glutathione (GSH) and phospholipids levels as well as superoxide dismutase (SOD, 220.127.116.11) and lactate dehydrogenase (LDH, 18.104.22.168) activities in rat brain after occlusion of common carotid arteries was investigated. Two experimental models were studied: 60 min ischaemia without reperfusion and 60 min ischaemia followed by 60 min reperfusion. Compared to sham-operated animals, ischaemia followed by reperfusion increased cytosolic LDH activity and mitochondrial lipid peroxide content and decreased the superoxide dismutase activity and mitochondrial total phospholipids level.
Preischaemic administration of ginkgo biloba extract (150 mg kg−1, p.o.) could normalize the SOD activity of the rat brain. The extract was also able to reduce the lipid peroxide and phospholipids contents of the mitochondrial rat brain. These effects could be explained on the basis of the antioxidant property of ginkgo biloba extract and suggests its beneficial role in the protection against post-ischaemic injury.
Reference: Calapai, Gioacchino, et al. “Neuroprotective effects of Ginkgo biloba extract in brain ischemia are mediated by inhibition of nitric oxide synthesis.” Life sciences 67.22 (2000): 2673-2683.
Neuroprotective effects of bilobalide, a component of Ginkgo biloba extract (EGb 761) in global brain ischemia and in excitotoxicity-induced neuronal death.
In this study, we compared the protective effect of bilobalide, a purified terpene lactone component of ginkgo biloba extract EGb 761, (definition see editorial) and EGb 761 against ischemic injury and against glutamate-induced excitotoxic neuronal death. In ischemic injury, we measured neuronal loss and the levels of mitochondrial DNA (mtDNA)-encoded cytochrome oxidase (COX) subunit III mRNA in vulnerable hippocampal regions of gerbils. At 7 days of reperfusion after 5 min of transient global ischemia, a significant increase in neuronal death and a significant decrease in COX III mRNA were observed in the hippocampal CA1 neurons. Oral administration of EGb 761 at 25, 50 and 100 mg/kg/day and bilobalide at 3 and 6 mg/kg/day for 7 days before ischemia progressively protected CA1 neurons from death and from ischemia-induced reductions in COX III mRNA. In rat cerebellar neuronal cultures, addition of bilobalide or EGb 761 protected in a dose-dependent manner against glutamate-induced excitotoxic neuronal death (effective concentration [EC (50)] = 5 microg/ml (12 microM) for bilobalide and 100 microg/ml for EGb 761. These results suggest that both EGb 761 and bilobalide are protective against ischemia-induced neuronal death in vivo and glutamate-induced neuronal death in vitro by synergistic mechanisms involving anti-excitotoxicity, inhibition of free radical generation, scavenging of reactive oxygen species, and regulation of mitochondrial gene expression.
Reference:Chandrasekaran, K., et al. “Neuroprotective effects of bilobalide, a component of Ginkgo biloba extract (EGb 761) in global brain ischemia and in excitotoxicity-induced neuronal death.” Pharmacopsychiatry 36 (2003): S89-94.
Effect of an extract of Ginkgo biloba on rat brain energy metabolism in hypoxia
The purpose of the present investigation was to determine brain energy metabolism under hypoxic conditions as influenced by an extract of Ginkgo biloba (EGB). Male Sprague-Dawley rats treated with EGB were exposed to hypobaric or hypoxic hypoxia, and at various time points during or after hypoxia the levels of high-energy phosphates and some substrates of glycolysis were measured in brain cortical tissue. Rats treated with EGB (100 mg/kg, intraperitoneally) survived hypobaric hypoxia for a much longer period than controls (e.g. controls: 3.9±1.8 min, EGB-treated: 23.6±10.5 min). The brain glucose level was elevated by EGB in most experimental series, and the lactate concentration was slightly lower than in control brains. The lowering of lactate/pyruvate ratio was due to the decreased level of lactate and to the enhanced concentration of pyruvate as well. When hypoxia was sufficiently severe the breakdown of high-energy phosphates was less pronounced in EGB-treated animals. After oral application of EGB for 14 days the rats survived hypobaric hypoxia for 25.7± 2.5 min whereas controls survived for 11.5±5.1 min. However, brain energy metabolism was not significantly influenced by this oral treatment. It is suggested that changes in brain energy metabolism and blood flow may contribute to the protective effect of EGB against hypoxia.
Reference: Tang, F., et al. “The effects of melatonin and Ginkgo biloba extract on memory loss and choline acetyltransferase activities in the brain of rats infused intracerebroventricularly with β-amyloid 1–40.” Life sciences 71.22 (2002): 2625-2631.
Phospholipid breakdown and choline release under hypoxic conditions: inhibition by bilobalide, a constituent of Ginkgo biloba
A marked increase of choline release from rat hippocampal slices was observed when the slices were superfused with oxygen-free buffer, indicating hypoxia-induced hydrolysis of choline-containing phospholipids. This increase of choline release was suppressed by bilobalide, an ingredient of Ginkgo biloba, but not by a mixture of ginkgolides. The EC50 value for bilobalide was 0.38 μM. In ex vivo experiments, bilobalide also inhibited hypoxia-induced choline release when given p.o. in doses of 2–20 mg/kg 1 h prior to slice preparation. The half-maximum effect was observed with 6 mg/kg bilobalide. A similar effect was noted after p.o. administration of 200 mg/kg EGb 761, a ginkgo extract containing approximately 3% of bilobalide. We conclude that ginkgo extracts can suppress hypoxia-induced membrane breakdown in the brain, and that bilobalide is the active constituent for this effect.
Reference: Klein, Jochen, Shyam S. Chatterjee, and Konrad Löffelholz. “Phospholipid breakdown and choline release under hypoxic conditions: inhibition by bilobalide, a constituent of Ginkgo biloba.” Brain research 755.2 (1997): 347-350.
St. John’s Wort (as .3% ext)
St. John’s wort
St. John’s wort has been used to treat a variety of conditions. Several brands are standardized for content of hypericin and hyperforin, which are among the most researched active components of St. John’s wort. St. John’s wort has been found to be superior to placebo and equivalent to standard antidepressants for the treatment of mild to moderate depression. Studies of St. John’s wort for the treatment of major depression have had conflicting results. St. John’s wort is generally well tolerated, although it may potentially reduce the effectiveness of several pharmaceutical drugs. (Am Fam Physician 2005;72:2249-54. Copyright © 2005 American Academy of Family Physicians.)
Ref: Lawvere, Silvana, and MARTIN C. Mahoney. “St. John’s wort.” Am Fam Physician 72.11 (2005): 2249-2254.
St. John’s Wort
This article reviews the historical background, active ingredients of St. John’s Wort and the major double-blind placebo-controlled studies. Despite the two major failed clinical trials conducted in American Research Centers, most of the data reviewed support that hypericum extracts are more effective than placebo for the treatment of mild to moderate depressive illness. The authors examine the likely reasons for the failed studies and also describe drug interactions and the side effects of St. John’s Wort. Those patients who are prescribed St. John’s Wort should be closely monitored.
Gupta, R. K., and H-J. Möller. “St. John’s Wort.” European archives of psychiatry and clinical neuroscience 253.3 (2003): 140-148.
St. John’s wort
At the end of 2013, there was much buzz about new studies showing that curing insomnia in people with depression might double the chance of a complete recovery from depression. The studies, financed by the National Institute of Mental Health, were welcomed as the most significant advance in treating depression since the introduction of the “selective serotonin re-uptake inhibitor” (SSRI), Prozac, twenty-five years ago. In effect, the new research findings turn conventional wisdom on its head, since they suggest that insomnia can be a main cause of depression, rather than just a symptom or a side effect, as previously assumed. If you can successfully treat a depressed person’s insomnia, according to the new view, you eliminate one of the main factors causing the depressed state.
New research findings turn conventional wisdom on its head suggesting that insomnia can be a main cause of depression rather than just a symptom or a side effect as previously assumed.
Ref: WORT, A. ST JOHN’S. “ST. JOHN’S WORT.” (2009).
Indinavir concentrations and St John’s wort
St John’s wort reduced the area under the curve of the HIV-1 protease inhibitor indinavir by a mean of 57% (SD 19) and decreased the extrapolated 8-h indinavir trough by 81% (16) in healthy volunteers. A reduction in indinavir exposure of this magnitude could lead to the development of drug resistance and treatment failure.
Reference: Piscitelli, Stephen C., et al. “Indinavir concentrations and St John’s wort.” The Lancet 355.9203 (2000): 547-548.DOI: http://dx.doi.org/10.1016/S0140-6736(99)05712-8
St John’s wort for depression—an overview and meta-analysis of randomised clinical trials
Objective: To investigate if extracts of Hypericum perforatum (St John’s wort) are more effective than placebo in the treatment of depression, are as effective as standard antidepressive treatment, and have fewer side effects than standard antidepressant drugs.
Design: Systematic review and meta-analysis of trials revealed by searches.
Trials: 23 randomised trials including a total of 1757 outpatients with mainly mild or moderately severe depressive disorders: 15 (14 testing single preparations and one a combination with other plant extracts) were placebo controlled, and eight (six testing single preparations and two combinations) compared hypericum with another drug treatment.
Main outcome measures: A pooled estimate of the responder rate ratio (responder rate in treatment group/responder rate in control group), and numbers of patients reporting and dropping out for side effects.
Results: Hypericum extracts were significantly superior to placebo (ratio = 2.67; 95% confidence interval 1.78 to 4.01) and similarly effective as standard antidepressants (single preparations 1.10; 0.93 to 1.31, combinations 1.52; 0.78 to 2.94). There were two (0.8%) drop outs for side effects with hypericum and seven (3.0%) with standard antidepressant drugs. Side effects occurred in 50 (19.8%) patients on hypericum and 84 (52.8%) patients on standard antidepressants.
Conclusion: There is evidence that extracts of hypericum are more effective than placebo for the treatment of mild to moderately severe depressive disorders. Further studies comparing extracts with standard antidepressants in well defined groups of patients and comparing different extracts and doses are needed.
Reference: Linde, Klaus, et al. “St John’s wort for depression—an overview and meta-analysis of randomised clinical trials.” Bmj 313.7052 (1996): 253-258.doi: http://dx.doi.org/10.1136/bmj.313.7052.253
Determination of St. John’s wort flavonoid-metabolites in rat brain through high performance liquid chromatography coupled with fluorescence detection
Flavonoids with the quercetin structure are widely distributed throughout the plant kingdom. Some effects such as their anti-oxidative and radical scavenging capacities are broadly discussed in literature. Furthermore, some Hypericum flavonoids show activity in depression-relevant animal model assays. So far, only one study concerning the pharmacokinetic profile of Hypericum perforatum (St. John’s wort, SJW) flavonoids has been reported, but no data concerning their bioavailability in the CNS is on-hand. Thus, we developed a method for the quantification of quercetin, tamarixetin and isorhamnetin, both metabolites of quercetin, in very low concentrations in the rat brain in order to investigate the ability of flavonoids to cross the blood–brain barrier. The brain samples for analysis were taken 4 h after feeding an oral dose of an alcoholic SJW extract or pure isoquercitrin. We found the presence of quercetin and isorhamnetin/tamarixetin after feeding a SJW extract at 7 ng/g brain and 35 ng/g brain, respectively. In addition, we examined blood plasma taken from the same rats to correlate plasma and brain levels. The plasma levels were 350 ng/mL for quercetin and 1006 ng/mL for isorhamnetin/tamarixetin after intake of SJW extract.
Reference: Paulke, Alexander, Manfred Schubert-Zsilavecz, and Mario Wurglics. “Determination of St. John’s wort flavonoid-metabolites in rat brain through high performance liquid chromatography coupled with fluorescence detection.” Journal of Chromatography B 832.1 (2006): 109-113.doi:10.1016/j.jchromb.2005.12.043
Mechanism of Action of St John’s Wort in Depression
Extracts of Hypericum perforatum L. (St John’s wort) are now successfully competing for status as a standard antidepressant therapy. Because of this, great effort has been devoted to identifying the active antidepressant compounds in the extract. From a phytochemical point of view, St John’s wort is one of the best-investigated medicinal plants. A series of bioactive compounds has been detected in the crude material, namely flavonol derivatives, biflavones, proantho-cyanidines, xanthones, phloroglucinols and naphthodianthrones.
Although St John’s wort has been subjected to extensive scientific studies in the last decade, there are still many open questions about its pharmacology and mechanism of action. Initial biochemical studies reported that St John’s wort is only a weak inhibitor of monoamine oxidase-A and -B activity but that it inhibits the synaptosomal uptake of serotonin, dopamine and noradrenaline (norepinephrine) with approximately equal affinity. However, other in vitro binding assays carried out using St John’s wort extract demonstrated significant affinity for adenosine, GABAa, GABAb and glutamate receptors. In vivo St John’s wort extract leads to a downregulation of β-adrenergic receptors and an upregulation of serotonin 5-HT2 receptors in the rat frontal cortex and causes changes in neurotransmitter concentrations in brain areas that are implicated in depression. In studies using the rat forced swimming test, an animal model of depression, St John’s wort extracts induced a significant reduction of immobility. In other experimental models of depression, including acute and chronic forms of escape deficit induced by Stressors, St John’s wort extract was shown to protect rats from the consequences of unavoidable stress. Recent neuroendocrine studies suggest that St John’s wort is involved in the regulation of genes that control hypothalamic-pituitary-adrenal axis function. With regard to the antidepressant effects of St John’s wort extract, many of the pharmacological activities appear to be attributable to the naphthodianthrone hypericin, the phloroglucinol derivative hyperforin and several flavonoids.
This review integrates new findings of possible mechanisms that may underlie the antidepressant action of St John’s wort and its active constituents with a large body of existing literature.
Reference:Butterweck, Veronika. “Mechanism of action of St John’s wort in depression.” CNS drugs 17.8 (2003): 539-562.
St John’s wort, hypericin, and imipramine: a comparative analysis of mRNA levels in brain areas involved in HPA axis control following short-term and long-term administration in normal and stressed rats
Reference: Butterweck, V., H. Winterhoff, and M. Herkenham. “St John’s wort, hypericin, and imipramine: a comparative analysis of mRNA levels in brain areas involved in HPA axis control following short-term and long-term administration in normal and stressed rats.” Molecular psychiatry 6.5 (2001): 547-564.
Inhibition of Synaptosomal Uptake of 3H-L-glutamate and 3H-GABA by Hyperforin, a Major Constituent of St. John’s Wort: The Role of Amiloride Sensitive Sodium Conductive Pathways
Extracts of St. John’s Wort are widely used for the treatment of depressive disorders. The active principles have not yet been finally elucidated. We have recently shown that hyperforin, a major active constituent of St. John’s Wort, not only inhibits the neuronal uptake of serotonin, norepinephrine and dopamine, but also that of L-glutamate and GABA. No other antidepressant compound exhibits a similar broad uptake inhibiting profile. To investigate this unique kind of property, kinetic analyses were performed regarding the uptake of 3H-L-glutamate and 3H-GABA into synaptosomal preparations of mouse brain. Michaelis-Menten kinetics revealed a reduction of Vmax (8.27 to 1.80 pmol/mg/min for 3H-L-glutamate, 2.76 to 0.77 pmol/mg/min for 3H-GABA) while Km was nearly unchanged in both cases, suggesting non-competitive inhibition. The unselective uptake inhibition by hyperforin could be mimicked by the Na+- ionophore monensin and by the Na+-K+-ATPase inhibitor ouabain. However, both mechanisms can be discarded for hyperforin. Several amiloride derivatives known to affect sodium conductance significantly enhance 3H-GABA and 3H-L-glutamate uptake and inhibit the uptake inhibition by hyperforin, while monensin or ouabain inhibition were not influenced. Selective concentrations of benzamil for amiloride sensitive Na+-channels and selective concentrations of 5′-ethylisopropylamiloride (EIPA) for the Na+-H+-exchangers both had an attenuating effect on the hyperforin inhibition of L-glutamate uptake, suggesting a possible role of amiloride sensitive Na+-channels and Na+-H+-exchangers in the mechanism of action of hyperforin.
reference: Wonnemann, M., A. Singer, and W. E. Müller. “Inhibition of synaptosomal uptake of 3H-L-glutamate and 3H-GABA by hyperforin, a major constituent of St. John’s Wort: the role of amiloride sensitive sodium conductive pathways.” Neuropsychopharmacology 23.2 (2000): 188-197.doi:10.1016/S0893-133X(00)00102-0
St. John’s wort extract Ze 117 (Hypericum perforatum) inhibits norepinephrine and serotonin uptake into rat brain slices and reduces 3-adrenoceptor numbers on cultured rat brain cells.
Despite almost forty years of widespread use, the mode of action of antidepressant drugs is still largely unknown. There is agreement that these drugs interact with central neurotransmission. Common findings are acute inhibitory actions on reuptake mechanisms for norepinephrine (NE) and for serotonin (5-HT) at presynaptic axons and chronic adaptive effects on neurotransmitter receptors on postsynaptic membranes. In particular, beta-adrenoceptor downregulation has been observed after chronic treatment with most antidepressants in vivo and in cell culture systems. We studied the effectiveness of Ze 117 (St. John’s wort) extract (Hypericum perforatum) on NE- and 5-HT-uptake into rat brain slices. Potency and efficacy of the Ze 117 extract were compared with those of tricyclic (TCA) and selective serotonin reuptake inhibitor (SSRI)-type antidepressants. A dose-dependent inhibition was seen on NE and 5-HT uptake into brain slices. The Ze 117 extract was more selective for the uptake of NE than for that of 5-HT. The maximal extent of uptake inhibition by Ze 117 extract was comparable to that of imipramine (IMI), desipramine (DMI) or fluvoxamine for 5-HT, but lower for NE transport, than that of the synthetic antidepressants. Chronic exposure (8 days) of confluent C6-cell cultures to Ze 117 extract resulted in a dose-dependent beta-adrenoceptor downregulation equal to that induced by DMI, a potent TCA. None of these effects could be achieved with either hypericin or hyperforin alone in a relevant dose range. Our results indicate that the St. John’s wort extract Ze 117 contains active, but as yet unknown antidepressant principles with effects comparable to those of TCAs.
Reference: Kientsch, Ulrich, et al. “St. John’s wort extract Ze 117 (Hypericum perforatum) inhibits norepinephrine and serotonin uptake into rat brain slices and reduces 3-adrenoceptor numbers on cultured rat brain cells.” Pharmacopsychiatry 34 (2001): S56-60.DOI: 10.1055/s-2001-15452
Long-term effects of St. John’s wort and hypericin on monoamine levels in rat hypothalamus and hippocampus
Hypericum perforatum L. (St. John’s wort) is one of the leading psychotherapeutic phytomedicines and, because of this, great effort has been devoted to clarifying its mechanism of action. Chronic effects of St. John’s wort and hypericin, one of its major active compounds, on regional brain amine metabolism have not been reported yet. We used a high-performance liquid chromatography system to examine the effects of short-term (2 weeks) and long-term (8 weeks) administration of imipramine, Hypericum extract or hypericin on regional levels of serotonin (5-HT), norepinephrine, dopamine and their metabolites in the rat brain. We focused our interest on the hypothalamus and hippocampus, as these brain regions are thought to be involved in antidepressant drug action. Imipramine (15 mg/kg, p.o.), Hypericum extract (500 mg/kg, p.o.), and hypericin (0.2 mg/kg, p.o.) given daily for 8 weeks significantly increased 5-HT levels in the hypothalamus (P<0.05). The 5-HT turnover was significantly lowered in both brain regions after 8 weeks of daily treatment with the Hypericum extract (both P<0.05). Consistent changes in catecholamine levels were only detected in hypothalamic tissues after long-term treatment. Comparable to imipramine, Hypericum extract as well as hypericin significantly decreased 3,4-dihydroxyphenylacetic acid and homovanillic acid levels in the hypothalamus (P<0.01). Our data clearly show that long-term, but not short-term administration of St. John’s wort and its active constituent hypericin modify levels of neurotransmitters in brain regions involved in the pathophysiology of depression.
Reference: Butterweck, Veronika, et al. “Long-term effects of St. John’s wort and hypericin on monoamine levels in rat hypothalamus and hippocampus.” Brain research 930.1 (2002): 21-29.doi:10.1016/S0006-8993(01)03394-7
Effects of oral administration of extracts of Hypericum perforatum (St John’s wort) on brain serotonin transporter, serotonin uptake and behaviour in mice
The pharmacological effects of extracts of Hypericum perforatum (St John’s wort) were characterized in-vitro and ex-vivo, in relation to its behavioural effects. In in-vitro experiments, St John’s wort inhibited brain synaptosomal [3H]serotonin uptake in mice with little effect on specific [3H]paroxetine binding. For selective serotonin-reuptake inhibitors (SSRIs), the IC50 value for [3H]serotonin uptake (molar concentration of unlabelled drug necessary to displace 50% of specific uptake) correlated well with the inhibition constant Ki value for [3H]paroxetine binding in mouse brain. Oral administration of St John’s wort (900 mg kg−1), paroxetine (1 mg kg−1) and sertraline (10 mg kg−1) brought about significant increases in the Km value for [3H]serotonin uptake into brain synaptosomes 4 h later, and only SSRIs suppressed specific [3H]paroxetine binding in mouse brain. St John’s wort and SSRIs significantly inhibited marble-burying behaviour in mice and the time-course of attenuation of this behaviour by St John’s wort was similar to that of [3H]serotonin uptake inhibition. In the forced swimming test, St John’s wort, but not SSRIs, suppressed the immobility time of mice after oral administration. These results provide the first in-vivo evidence to suggest that the mode of antidepressant action of St John’s wort differs from that of SSRIs. Thus, this study may have a significant impact on phytotherapy with St John’s wort.
reference: Hirano, Kazufumi, et al. “Effects of oral administration of extracts of Hypericum perforatum (St John’s wort) on brain serotonin transporter, serotonin uptake and behaviour in mice.” Journal of pharmacy and pharmacology 56.12 (2004): 1589-1595.DOI: 10.1211/0022357045039
Glutamine (as L-glutamine HCl)
THE ROLE OF GLUTAMINE IN PROTEIN BIOSYNTHESIS IN TISSUE CULTURE
- Glutamine in the medium of a human carcinoma cell (strain HeLa) was incorporated directly into the cell protein without preliminary degradation.
Virtually all of the glutamine residues of newly synthesized protein arose from the glutamine of the medium.
- Glutamine and glutamic acid acted independently in protein synthesis, each serving as the direct precursor for its corresponding residue in the protein.
- Neither glutamine amide N nor ammonia was a precursor of a-amino N of the protein.
- The carbon chain of glutamine served as a precursor of aspartic acid and proline, probably via glutamic acid.
- The preparation of N15 – and C4-labeled L-glutamine by means of enzymatic synthesis is described.
Reference: Levintow, Leon, Harry Eagle, and K. A. Piez. “The role of glutamine in protein biosynthesis in tissue culture.” Journal of Biological Chemistry 227.2 (1957): 929-941.
Structure-Based Design, Synthesis, and Biological Evaluation of Irreversible Human Rhinovirus 3C Protease Inhibitors. 4. Incorporation of P1 Lactam Moieties as l-Glutamine Replacements
The structure-based design, chemical synthesis, and biological evaluation of various human rhinovirus (HRV) 3C protease (3CP) inhibitors which incorporate P1 lactam moieties in lieu of an l-glutamine residue are described. These compounds are comprised of a tripeptidyl or peptidomimetic binding determinant and an ethyl propenoate Michael acceptor moiety which forms an irreversible covalent adduct with the active site cysteine residue of the 3C enzyme. The P1-lactam-containing inhibitors display significantly increased 3CP inhibition activity along with improved antirhinoviral properties relative to corresponding l-glutamine-derived molecules. In addition, several lactam-containing compounds exhibit excellent selectivity for HRV 3CP over several other serine and cysteine proteases and are not appreciably degraded by a variety of biological agents. One of the most potent inhibitors (AG7088, mean antirhinoviral EC90 ≈ 0.10 μM, n = 46 serotypes) is shown to warrant additional preclinical development to explore its potential for use as an antirhinoviral agent.
Dragovich, Peter S., et al. “Structure-based design, synthesis, and biological evaluation of irreversible human rhinovirus 3C protease inhibitors. 4. Incorporation of P1 lactam moieties as L-glutamine replacements.” Journal of medicinal chemistry 42.7 (1999): 1213-1224.DOI: 10.1021/jm9805384
AN L-GLUTAMINE REQUIREMENT FOR INTERCELLULAR ADHESION
Intercellular adhesion presumably involves components of the cell surface, but the chemical nature of these substances is not known. The present studies suggest that complex carbohydrates are required for the adhesion of at least one type of animal cell. Single cells obtained from “embryoid bodies,” the ascites-grown form of a mouse teratoma, aggregated in a complex tissue culture medium, but not in a glucose balanced salts solution. The active component of the tissue culture medium was identified as L-glutamine, and the only compounds found to replace it were the hexosamines D-glucosamine and D-mannosamine. A variety of studies indicated that the three compounds were active as a consequence of metabolic reactions. These results are consistent with known metabolic pathways and indicate that the conversion of nonadhesive to adhesive teratoma cells requires the synthesis of glycoproteins, glycolipids, and/or polysaccharides.
Reference:Oppenheimer, Steven B., et al. “An L-glutamine requirement for intercellular adhesion.” Proceedings of the National Academy of Sciences 63.4 (1969): 1395-1402.
Oxidative damage to brain proteins, loss of glutamine synthetase activity, and production of free radicals during ischemia/reperfusion-induced injury to gerbil brain
Free radical-mediated oxidative damage has been implicated in tissue injury resulting from ischemia/reperfusion events. Global cortical ischemia/reperfusion injury to Mongolian gerbil brains was produced by transient occlusion of both common carotid arteries. Protein oxidation, as measured by protein carbonyl content, increased significantly during the reperfusion phase that followed 10 min of ischemia. The activity of glutamine synthetase, an enzyme known to be inactivated by metal-catalyzed oxidation reactions, decreased to 65% of control levels after 2 hr of reperfusion that followed 10 min of ischemia. We also report that the free radical spin trap N-tert-butyl-alpha-phenylnitrone [300 mg/kg (body weight)] administered 60 min before ischemia/reperfusion is initiated, partially prevents protein oxidation and protects from loss of glutamine synthetase activity. In addition, we report a N-tert-butyl-alpha-phenylnitrone-dependent nitroxide radical obtained in the lipid fraction of the ischemia/reperfusion-lesioned brains, but there was very little radical present in the comparable sham-operated control brains. These data strengthen the previous observation utilizing in vivo-trapping methods, that free radical flux is increased during the reperfusion phase of the ischemia-lesioned gerbil brain. The loss of glutamine synthetase would be expected to increase the levels of brain L-glutamate. Thus, the oxidative inactivation of glutamine synthetase may be a critical factor in the neurotoxicity produced after cerebral ischemia/reperfusion injury.
Reference: Oliver, C. N., et al. “Oxidative damage to brain proteins, loss of glutamine synthetase activity, and production of free radicals during ischemia/reperfusion-induced injury to gerbil brain.” Proceedings of the National Academy of Sciences 87.13 (1990): 5144-5147.
HIGH AFFINITY UPTAKE OF l-GLUTAMINE IN RAT BRAIN SLICES
—l-Glutamine is taken up into rat brain slices by a specific‘high affinity’uptake system (Km 52 μm) which is not influenced by high concentrations of l-glutamate and l-asparagine. The uptake system appears to be associated with cellular structures that do not survive homogenization under conditions which yield synaptosomes. The‘high affinity’uptake of glutamine is dependent on the external sodium ion concentration and can be inhibited by p-chloromercuriphenylsulphonate, amino-oxyacetic acid, ouabain, dibenamine and allylglycine. The effects of several inhibitors indicate that l-asparagine uptake is mediated by a system different from the‘high affinity’system mediating l-glutamine uptake.
Reference: Balcar, V. J., and G. A. R. Johnston. “HIGH AFFINITY UPTAKE OF l‐GLUTAMINE IN RAT BRAIN SLICES.” Journal of neurochemistry 24.5 (1975): 875-879. DOI: 10.1111/j.1471-4159.1975.tb03650.x
QUANTITATIVE METHODS FOR MEASURING THE HISTOCHEMICAL DISTRIBUTION OF ALANINE, GLUTAMATE AND GLUTAMINE IN BRAIN
Reference: Young, Richard L., and Oliver H. Lowry. “QUANTITATIVE METHODS FOR MEASURING THE HISTOCHEMICAL DISTRIBUTION OF ALANINE, GLUTAMATE AND GLUTAMINE IN BRAIN*.” DOI: 10.1111/j.1471-4159.1966.tb05873.x
Accumulation of glutamic acid in isolated brain tissue
Reference: Stern, J. R., et al. “Accumulation of glutamic acid in isolated brain tissue.” Biochemical Journal 44.4 (1949): 410.
THE STRUCTURAL SPECIFICITY OF THE HIGH AFFINITY UPTAKE OF l-GLUTAMATE AND l-ASPARTATE BY RAT BRAIN SLICES
Abstract— The high affinity uptake system for l-glutamate and l-aspartate in rat cerebral cortex may not be specific for these likely excitatory synaptic transmitters, as threo-3-hydroxy-dl-aspartate, l-cysteinesulphinate, l-cysteate and d-aspartate strongly inhibit the observed high affinity uptake of l-[3H]glutamate by rat brain slices in a manner consistent with linear competitive inhibition. These substances should therefore be considered as possible substrates for the transport system. Each of these four acidic amino acids excites central neurones in a manner similar to excitation induced by l-glutamate, and as each might occur in brain tissue, their possible synaptic role should be investigated.
l-Glutamate high affinity uptake was shown to be sodium-dependent, but under certain conditions appeared to be less sensitive than GABA uptake to changes in the external sodium ion concentration, and to drugs which modify sodium ion movements. This may be relevant to the efficiency of the glutamate uptake process during synaptic depolarization induced by glutamate.
l-Glutamate high affinity uptake was inhibited in a relatively nonspecific manner by a variety of drugs including mercurials and some electron transport inhibitors.
Reference: Balcar, V. J., and G. A. R. Johnston. “The structural specificity of the high affinity uptake of L‐glutamate and L‐aspartate by rat brain slices.” Journal of neurochemistry 19.11 (1972): 2657-2666.
Isolation and properties of γ-L-glutamylcyclotransferase from human brain
Reference: Orlowski, Marian, Paul G. Richman, and Alton Meister. “Isolation and properties of γ-L-glutamylcyclotransferase from human brain.” Biochemistry 8.3 (1969): 1048-1055.DOI: 10.1021/bi00831a036
Effects of Soy Lecithin Phosphatidic Acid and Phosphatidylserine Complex (PAS) on the Endocrine and Psychological Responses to Mental Stress
Phosphatidylserine, derived from cow brains, has been shown previously to dampen the ACTH and cortisol response to physical stress. Further research investigated the influence of soy lecithin phosphatidylserine supplementation on mood and heart rate when faced with an acute stressor. In this study, we investigated the effects of soy lecithin phosphatidic acid and phosphatidylserine complex (PAS) supplementation on pituitary adrenal reactivity (ACTH, cortisol) and on the psychological response (Spielberger State Anxiety Inventory stress subscale) to a mental and emotional stressor. Four groups of 20 subjects were treated for three weeks with daily dosages of either 400 mg PAS, 600 mg PAS, 800 mg PAS, or placebo before exposure to the Trier Social Stress Test (TSST). Treatment with 400 mg PAS resulted in a pronounced blunting of both serum ACTH and cortisol, and salivary cortisol responses to the TSST, but did not affect heart rate. The effect was not seen with larger doses of PAS. With regard to the psychological response, 400 mg PAS seemed to exert a specific positive effect on emotional responses to the TSST. While the placebo group showed the expected increase in distress after the test, the group treated with 400 mg PAS showed decreased distress. These data provide initial evidence for a selective stress dampening effect of PAS on the pituitary–adrenal axis, suggesting the potential of PAS in the treatment of stress related disorders.
Reference:Hellhammer, J., et al. “Effects of soy lecithin phosphatidic acid and phosphatidylserine complex (PAS) on the endocrine and psychological responses to mental stress.” Stress 7.2 (2004): 119-126. DOI:10.1080/10253890410001728379
In vivo and in vitro modulation of central type benzodiazepine receptors by phosphatidylserine
The in vivo and in vitro modulation of central benzodiazepine binding sites (BDZ-R) by phosphatidylserine purified from bovine cerebral cortex (BC-PS) was studied. Five days i.p. administration of 15 mg/kg/day of BC-PS liposomes increased the maximal number of binding sites (Bmax) for [3H]flunitrazepam in cerebral cortical membranes. In contrast, the density of hippocampal benzodiazepine recognition binding sites decreased. In cerebellar membranes, BC-PS treatment did not alter the characteristics of [3H]flunitrazepam binding. Similar experiments using phosphatidylcholine extracted from bovine brain (BC-PC) resulted in no changes in the [3H]flunitrazepam binding in the 3 neural structures studied. Confirming previous results, rats submitted to an acute swimming stress showed a decrease in the density of cerebral cortex BDZ-R. Animals treated with BC-PS liposomes before stress showed cortical [3H]flunitrazepam binding significantly below treated, unstressed animals but not below controls. The effects of BC-PS liposomes appeared to be selective for the central type of BDZ-R since no changes were observed in [3H]RO 5-4864 binding, a radioligand specific for the peripheral type BDZ-R. Preincubation of cerebral cortical and cerebellar synaptosomal membranes with BC-PS liposomes (1–300 μg per assay) significantly increased in a concentration-dependent manner (up to 100 μg) the [3H]flunitrazepam binding. Scatchard analysis revealed changes in the apparent affinity without alterations in the Bmax. Very similar results were obtained using a purified PS from spinal cord. BC-PC, phosphatidylinositol, phosphatidic acid and the lyso derivatives of PS and PC (lysoPS and lysoPC) were found to be ineffective. The facilitating effects of BC-PS and γ-aminobutyric acid (GABA) on [3H]flunitrazepam binding were not additive. As with BC-PS, the diglyceride cardiolipine added to cerebral cortical and cerebellar membranes induced a concentration dependent (up to 25 μg) increase in [3H]flunitrazepam binding. Higher concentrations of cardiolipine produced a decrease of [3H]flunitrazepam binding. These results indicate that the central type benzodiazepine receptors are under the modulatory action of PS and suggest that this endogenous phospholipid may play a regulatory role on the benzodiazepine/GABA receptor function.
Reference: de Stein, Miguelina Levi, Jorge H. Medina, and Eduardo De Robertis. “In vivo and in vitro modulation of central type benzodiazepine receptors by phosphatidylserine.” Molecular Brain Research 5.1 (1989): 9-15.doi:10.1016/0169-328X(89)90012-0
Subunit identification and reconstitution of the N-type Ca2+ channel complex purified from brain
Calcium channels play an important role in regulating various neuronal processes, including synaptic transmission and cellular plasticity. The N-type calcium channels, which are sensitive to omega-conotoxin, are involved in the control of transmitter release from neurons. A functional N-type calcium channel complex was purified from rabbit brain. The channel consists of a 230-kilodalton subunit (alpha 1B) that is tightly associated with a 160-kilodalton subunit (alpha 2 delta), a 57-kilodalton subunit (beta 3), and a 95-kilodalton glycoprotein subunit. The complex formed a functional calcium channel with the same pharmacological properties and conductance as those of the native omega-conotoxin-sensitive calcium channel in neurons.
Reference: Sakai, Masashi, Hideyuki Yamatoya, and Satoshi Kudo. “Pharmacological effects of phosphatidylserine enzymatically synthesized from soybean lecithin on brain functions in rodents.” Journal of nutritional science and vitaminology 42.1 (1996): 47-54.DOI: 10.1126/science.8392754
Pharmacological Effects of Phosphatidylserine Enzymatically Synthesized from Soybean Lecithin on Brain Functions in Rodents
Soybean transphosphatidylated phosphatidylserine (SBtPS) was prepared from soybean phosphatidylcholine by transphosphatidylation using phospholipase D, and the fatty acids composition and pharmacological properties were compared with those of bovine brain cortex-derived phosphatidylserine (BC-PS) which was reported to improve cognitive disorders of senile dementia patients by oral administration (300mg/day). The molecular species of SB-tPS are rich in linoleic and palmitic acids whereas those of BC-PS are stearic and oleic acids. Despite the differences in fatty acid composition, SB-tPS displayed significant activities on the increase in brain glucose concentrations in mice (79mg/kg, i.v.) and the restoration of scopolamine-induced amnesia in rats (60mg/kg, i.p.) as did BC-PS. These results suggest the possibility that SB-tPS may prevent and/or improve senile dementia by oral administration.
Reference: Sakai, Masashi, Hideyuki Yamatoya, and Satoshi Kudo. “Pharmacological effects of phosphatidylserine enzymatically synthesized from soybean lecithin on brain functions in rodents.” Journal of nutritional science and vitaminology 42.1 (1996): 47-54.doi.org/10.3177/jnsv.42.47
PHARMACOLOGICAL EFFECTS OF PHOSPHATIDYLSERINE LIPOSOMES: THE ROLE OF LYSOPHOSPHATIDYLSERINE
Unique among the phospholipids, phosphatidylserine depresses brain energy metabolism when injected intravenously into mice in the form of sonicated liposomes. The possibility that this effect results from a metabolic transformation of phosphatidylserine is examined in this paper.
A strong enhancement of the phosphatidylserine effect is induced by the incubation of liposomes with rat serum. Similar phosphatidylserine activation is observed after the incubation of the phospholipid with purified phospholipase A2 from pancreas. In both cases phosphatidylserine is split into the deacylated derivative, lysophosphatidylserine.
Lysophosphatidylserine reproduces with greater efficacy the effect of phosphatidylserine on brain energy metabolism. Other lysophospholipids are not effective.
It is concluded that the pharmacological effects of phosphatidylserine liposomes is due to the generation of lysophosphatidylserine.
Reference: Bigon, E., et al. “Pharmacological effects of phosphatidylserine liposomes: the role of lysophosphatidylserine.” British journal of pharmacology 67.4 (1979): 611-616.DOI: 10.1111/j.1476-5381.1979.tb08708.x
A REVIEW OF PHOSPHATIDYLSERINE PHARMACOLOGICAL AND CLINICAL EFFECTS. IS PHOSPHATIDYLSERINE A DRUG FOR THE AGEING BRAIN?
Reference: PEPEU, GIANCARLO, ILEANA MARCONCINI PEPEU, and LUIGI AMADUCCI. “A review of phosphatidylserine pharmacological and clinical effects. Is phosphatidylserine a drug for the ageing brain?.” Pharmacological research 33.2 (1996): 73-80.doi:10.1006/phrs.1996.0013
Effects of chlorpromazine on phosphatidylserine biosynthesis in rat PUP brain exposed to ethanol in utero
Phosphatidylserine biosynthesis in rat pup brain was examined by assaying the serine base-exchange enzyme activity in the microsomal and plasma membrane fractions, and by measuring the incorporation of [3H]serine into phosphatidylserine in brain slices and in the intact brain. Chlorpromazine, either added in vitro into the incubation system or administered to animals via i.p. injection or feeding a liquid diet, gave rise to an increase in the phosphatidylserine biosynthesis activity. Ethanol administered in the form of a liquid diet to pregnant rats (day 11-birth) resulted in a decrease in phosphatidylserine biosynthesis in the newborn and developing brain. The ethanol-induced decrease in phosphatidylserine biosynthetic activity could be reversed by adding chlorpromazine to the ethanol diet. Results demonstrate that phosphatidylserine biosynthesis in the neonatal brain is affected in opposite directions by chlorpromazine and ethanol. This poses the possibility that chlorpromazine administration may be effective in alleviating the deleterious effects caused by the decreased phosphatidylserine biosynthesis in brain due to in utero ethanol exposure.
Reference: Rhodes, Philip G., Zhong-Yi Hu, and Grace Y. Sun. “Effects of chlorpromazine on phosphatidylserine biosynthesis in rat pup brain exposed to ethanol in utero.” Neurochemistry international 22.1 (1993): 75-80.doi:10.1016/0197-0186(93)90071-C
Age-dependent spontaneous EEG bursts in rats: Effects of brain phosphatidylserine
During aging, male Sprague-Dawley rats display increasing frequency of bursts of seizure-like EEG patterns. They also have a decreased retention of passive avoidance response and a loss of spontaneous alternation in a Y maze. A study was made on the effects of chronic administration of phosphatidylserine in aged rats. It was found that BC-PS reduced by 65% the number of seizures, and by 70% their duration. It also facilitated retention of passive avoidance and of spontaneous alternation behavior. These results suggest that phosphatidylserine can affect electrophysiological and behavioral parameters in aged rats probably by counteracting age-related biochemical changes.
Reference: Aporti, Ferrante, et al. “Age-dependent spontaneous EEG bursts in rats: effects of brain phosphatidylserine.” Neurobiology of aging 7.2 (1986): 115-120.doi:10.1016/0197-4580(86)90149-1
Effect of Docosahexaenoic Acid on the Synthesis of Phosphatidylserine in Rat Brain Microsomes and C6 Glioma Cells
Abstract: Docosahexaenoic acid (22:6n-3) is the major polyunsaturated fatty acid (PUFA) in the CNS and accumulates particularly in phosphatidylserine (PS). We have investigated the effect of the 22:6n-3 compositional status on the synthesis of PS. The fatty acid composition of brain microsomes from offspring of rats artificially reared on an n-3-deficient diet showed a dramatic reduction of 22:6n-3 content (1.7 ± 0.1%) when compared with control animals (15.0 ± 0.2%). The decrease was accompanied by an increase in docosapentaenoic acid (22:5n-6) content, which replaced the 22:6n-3 phospholipids with 22:5n-6 molecular species, as demonstrated using HPLC/electrospray mass spectrometry. The n-3 deficiency did not affect the total amount of polyunsaturated phospholipids in brain microsomes; however, it was associated with a decrease in the total polyunsaturated PS content and with increased levels of 1-stearoyl-2-docosapentanoyl (18:0/22:5n-6) species, particularly in phosphatidylcholine. Incorporation of [3H]serine into PS in rat brain microsomes from n-3-deficient animals was slightly but significantly less than that of the control animals. Similarly, C6 glioma cells cultured for 24 h in 22:6n-3-supplemented media (10–40 µM) showed a significant increase in the synthesis of [3H]PS when compared with unsupplemented cells. Our data show that neuronal and glial PS synthesis is sensitive to changes in the docosahexaenoate levels of phospholipids and suggest that 22:6n-3 may be a modulator of PS synthesis.
Reference: Garcia, Martha C., et al. “Effect of docosahexaenoic acid on the synthesis of phosphatidylserine in rat brain microsomes and C6 glioma cells.” Journal of neurochemistry 70.1 (1998): 24-30.DOI: 10.1046/j.1471-4159.1998.70010024.x
The Role of Phosphatidylserine Decarboxylase in Brain Phospholipid Metabolism
Abstract: In brain, phosphatidylethanolamine can be synthesized from free ethanolamine either by a pathway involving the formation of CDP-ethanolamine and its transfer to diglyceride, or by base-exchange of ethanolamine with existing phospholipids. Although de novo synthesis from serine has also been demonstrated, the metabolic pathway involved is not known. The enzyme phosphatidylserine decarboxylase appears to be involved in the synthesis of much of the phosphatidylethanolamine in liver, but the significance of this route in brain has been challenged. Our in vitro studies demonstrate the existence of phosphatidylserine decarboxylase activity in rat brain and characterize some of its properties. This enzyme is localized in the mitochondrial fraction, whereas the enzymes involved in base-exchange and the cytidine pathway are localized to microsomal membranes. Parallel in vivo studies showed that after the intracranial injection of L-[G-3H] serine, the specific activity of phosphatidylserine was greater in the microsomal fractions than in the mitochondrial fraction, whereas the opposite was true for phosphatidylethanolamine. When L-[U-14C]serine and [13H]ethanolamine were simultaneously injected, the 14C/3H ratio in mitochondrial phosphatidylethanolamine was 10 times that in microsomal phosphatidylethanolamine. The results demonstrate that serine is incorporated into the base moiety of phosphatidylethanolamine primarily through the decarboxylation of phosphatidylserine in brain mitochondria. A minimal value of 7% for the contribution of phosphatidylserine decarboxylase to whole-brain phosphatidylethanolamine synthesis can be estimated from the in vivo data.
Reference: Butler, Madeline, and Pierre Morell. “The role of phosphatidylserine decarboxylase in brain phospholipid metabolism.” Journal of neurochemistry 41.5 (1983): 1445-1454.DOI: 10.1111/j.1471-4159.1983.tb00844.x
Bacopa Monnier (20% Bacosides)
Harshad, C. Barbhaiya, Rejeshwari P. Desai, Vinod S. Saxena, K. Pravina, P. Wasim, P. Geetharani, J. Joshua Allan, K. Venkateshwarlu and A. Amit. Efficacy and Tolerability of BacoMind® on Memory Improvement in Elderly Participants- A Double Blind Placebo Controlled Study. Journal of Pharmacology and Toxicology, 2008: 3(6); 425-434.
P.D. Usha, P. Wasim, J.A. Joshua, P. Geetharani, B. Murali, A.S. Mayachari, K. Venkateshwarlu, V.S. Saxena, M. Deepak and A. Amit. BacoMind®: A Cognitive Enhancer in Children Requiring Individual Education Programme. Journal of Pharmacology and Toxicology, 2008; 3(4): 302-310
Pravina K, Ravindra KR, Goudar KS, Vinod DR, Joshua AJ, Wasim P, Venkateshwarlu K, Saxena VS, Amit A. Safety evaluation of BacoMind® in healthy volunteers: A phase I study. Phytomedicine 2007; 14: 301-08.
Deb DD, Kapoor P, Dighe RP, Padmaja R, Anand MS, D’Souza P, Deepak M, Murali B, Amit A. In vitro safety evaluation and anticlastogenic effect of BacoMind® on human lymphocytes. Biomed Environ Sci. 2008; 21:7-23.
Morgan, A. , Stevens J.Does Bacopa monnieri improve memory performance in older persons? Results of a randomized, placebo-controlled, double-blind trial.Journal of Alternative and Complementary Medicine, 2010 Jul;16(7):753-9. doi: 10.1089/acm.2009.0342.
E. Ernst. Herbal remedies for anxiety – a systematic review of controlled clinical trials
Phytomedicine 2006; 13(3): 205-208.
Naila Sheikha, Ausaf Ahmada,Kiran Babu Siripurapua Vijaya Kumar Kuchibhotlaa,Satyawan Singhb,Gautam Palita, Effect of Bacopa monniera on stress induced changes in plasma corticosterone and brain monoamines in rats. Journal of Ethnopharmacology 2007;111(3): 671–676.
Sangeeta Raghav, Harjeet Singh, […], and O.P. Asthana.Randomized controlled trial of standardized Bacopa monniera extract in age-associated memory impairment. Indian J Psychiatry.2006 Oct-Dec;48(4):238-242.
Neetu Saini, Devinder Singh, Rajat Sandhir. Neuroprotective Effects of Bacopa monnieri in Experimental Model of Dementia. Neurochemical Research 2012; 37(9):1928-1937.
Thangarajan Sumathi, Chandrasekar Shobana, Johnson Christinal, Chandran Anusha. Protective Effect of Bacopa monniera on Methyl Mercury-Induced Oxidative Stress in Cerebellum of Rats. Cellular and Molecular Neurobiology 2012; 32(6): 979-987.
Divya Vohora, S.N Pal, K.K Pillai. Protection from phenytoin-induced cognitive deficit by Bacopa monniera, a reputed Indian nootropic plant. Journal of Ethnopharmacology 2000; 71(3):383–390.
Russo ,F. Borrelli. Bacopa monniera, a reputed nootropic plant: an overview. Phytomedicine 2005; 12(4): 305-317.
Lodha R, Bagga A. Traditional Indian systems of medicine. Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India. Annals of the Academy of Medicine, Singapore [2000, 29(1):37-41].
Gohil KJ, Patel JA. A review on Bacopa monniera: Current research and future prospects. Int J Green Pharm 2010;4:1-9
Vikas Kumar. Potential medicinal plants for CNS disorders: an overview. Phytotherapy Research 2006; 20(12): 1023-1035
Jobin Mathew, Jes Paul, M.S. Nandhu, C.S. Paulose. Bacopa monnieri and Bacoside-A for ameliorating epilepsy associated behavioral deficits. Fitoterapia 2010; 81(5): 315-322
Parris M. Kidd, PhD. A Review of Nutrients and Botanicals in the Integrative Management of Cognitive Dysfunction. Alternative Medicine Review1999; 4(3): 144-161.
Goswami S, Saoji A, Kumar N, Thawani V, Tiwari M, Thawani M. Effect of Bacopa monnieri on Cognitive functions in Alzheimer’s disease patients. International Journal of Collaborative Research on Internal Medicine & Public Health. 2011; 3(4):285-293.
Jerome Sarris,Alexander Panossian,Isaac Schweitzer,Con Stough,Andrew Scholey. Herbal medicine for depression, anxiety and insomnia: A review of psychopharmacology and clinical evidence. European Neuropsychopharmacology 2011;21(12): 841–860.
Annette Morgan and John Stevens. Does Bacopa monnieri Improve Memory Performance in Older Persons? Results of a Randomized, Placebo-Controlled, Double-Blind Trial. The Journal of Alternative and Complementary Medicine. July 2010, 16(7): 753-759.
Con Stough,Luke A. Downey,Jenny Lloyd,Beata Silber,Stephanie Redman,Chris Hutchison,Keith Wesnes and Pradeep J. Nathan. Examining the nootropic effects of a special extract of Bacopa monniera on human cognitive functioning: 90 day double-blind placebo-controlled randomized trial. Phytotherapy Research 2008; 22(12): 1629-1634.
Stimulant Effect of 2-Dimethylaminoethanol—Possible Precursor of Brain Acetylcholine
Reference: Pfeiffer, Carl C., et al. “Stimulant effect of 2-dimethylaminoethanol—possible precursor of brain acetylcholine.” Science 126.3274 (1957): 610-611.DOI: 10.1126/science.126.3274.610
Is 2-dimethylaminoethanol (deanol) indeed a precursor of brain acetylcholine? A gas chromatographic evaluation.
Acute administration of deanol-p-acetamidobenzoate (Deaner; deanol) has been reported to elevate brain choline (CH) and acetylcholine (ACh) levels. We have developed a specific and sensitive gas chromatographic assay to measure deanol levels in tissue and have applied this assay to our studies of the effect of acute deanol administration on deanol, ACh and Ch levels in rodent brains. Details of the method are described in this text. This procedure is quantitative and yields reproducible results over a wide range of deanol concentrations (0.30-200 nmol). Seven endogenous and pharmacological parameters have been studied using this procedure. In control rodent brain, liver, heart, lung and plasma, we detected no free endogenous deanol (less than 1 nmol/g). After deanol administration, we were able to detect deanol in tissue and have attempted to determine a relationship between these levels and values of ACh in the same tissue. Regardless of deanol pretreatment time (1-30 minutes) or doses (33.3-3000 mg/kg i.p.) used, we detected no increase in mouse whole brain ACh levels. Likewise, there was no detectable elevation in ACh levels in rat whole brain, cortex, striatum or hippocampus after a 15-minute pretreatment with 550 mg/kg of deanol (i.p.). The only elevation in ACh levels which we detected occurred selectively in the striatum of mice pretreated with a massive dose (900 mg/kg i.p.) of deanol for 30 minutes. This selective increase in striatal ACh levels oculd not, however, be related to levels of deanol in the striatum because there was no greater accumulation of deanol in the striatum than in other brain areas tested or in whole brain. These data do not confirm the results of other investigators who reported elevations in whole brain or striatal ACh levels after acute administration of lower doses of deanol. The data emphasize the need for further investigation into the mode of action of deanol and question its suggested role as an immediate precursor of ACh synthesis in the central nervous system.
Reference: Zahniser, NANCY R., D. A. V. I. D. Chou, and I. S. R. A. E. L. Hanin. “Is 2-dimethylaminoethanol (deanol) indeed a precursor of brain acetylcholine? A gas chromatographic evaluation.” Journal of Pharmacology and Experimental Therapeutics 200.3 (1977): 545-559.
Dimethylaminoethanol (deanol) metabolism in rat brain and its effect on acetylcholine synthesis.
Specific methods utilizing combined gas chromatography mass spectrometry were used to measure the metabolism of [2H6] deanol and its effects on acetylcholine concentration in vitro and in vivo. In vitro [2H6]deanol was rapidly taken up by rat brain synaptosomes, but was neither methylated nor acetylated. [2H6]Deanol was a weak competitive inhibitor of the high affinity transport of [2H4]choline, thus reducing the synthesis of [2H4]acetylcholine. In vivo [2H6]deanol was present in the brain after i.p. or p.o. administration, but was not methylated or acetylated. Treatment of rats with [2H6]deanol significantly increased the concentration of choline in the plasma and brain but did not alter the concentration of acetylcholine in the brain. Treatment of rats with atropine (to stimulate acetylcholine turnover) or with hemicholinium-3 (to inhibit the high affinity transport of choline) did not reveal any effect of [2H6]deanol on acetylcholine synthesis in vivo. However, since [2H6]deanol did increase brain choline, it may prove therapeutically useful when the production of choline is reduced or when the utilization of choline for the synthesis of acetylcholine is impaired.
Reference: Jope, RICHARD S., and DONALD J. Jenden. “Dimethylaminoethanol (deanol) metabolism in rat brain and its effect on acetylcholine synthesis.” Journal of Pharmacology and Experimental Therapeutics 211.3 (1979): 472-479.
Effect of choline, phosphorylcholine and dimethylaminoethanol on brain acetylcholine level in the rat
The effect of the administration of choline (Ch), phosphorylcholine (PCh) and dimethylaminoethanol (DMAE) on acetylcholine (ACh) level in the cerebral cortex and the caudate nucleus was investigated in rats killed by focussed microwave radiations. Ch administered i.p. or i.v. up to the dose of 120 mg/Kg caused neither behavioural effects nor changes in ACh level. Similarly no effects were detected following administration of equimolar doses of PCh or DMAE. PCh (226 mg/Kg i.p.) exerted a partial antagonism toward the decrease in striatal ACh induced by intraventricular administration of hemicholinium (HC-3). The intraventricular administration of PCh, Ch but not of DMAE also antagonized the effect of HC-3 on striatal ACh level but not on cortical ACh.
Reference: Pedata, Felicita, Andrzej Wieraszko, and Giancarlo Pepeu. “Effect of choline, phosphorylcholine and dimethylaminoethanol on brain acetylcholine level in the rat.” Pharmacological research communications 9.8 (1977): 755-761.doi:10.1016/S0031-6989(77)80067-2
THE EFFECTS OF 2-DIMETHYLAMINOETHANOL ON BRAIN PHOSPHOLIPID METABOLISM
Reference: Ansell, G. B., and S. Spanner. “THE EFFECTS OF 2‐DIMETHYLAMINOETHANOL ON BRAIN PHOSPHOLIPID METABOLISM.” Journal of neurochemistry 9.3 (1962): 253-263.DOI: 10.1111/j.1471-4159.1962.tb09447.x
Comparative Studies on the Metabolism of β-Dimethylaminoethanol in the Mouse Brain and Liver Following Administration of β-Dimethyl-aminoethanol and Its p-Chlorophenoxyacetate, Meclofenoxate
1) After intravenous treatments of mice with equimolar doses of 14C-labeled β-dimethylaminoethanol (DMAE*) or its p-chlorophenoxyacetate [MF (DMAE*)], brain levels of DMAE* were found to be much higher in the latter treatment, due to the better penetration of the ester derivative, followed by hydrolysis. 2) DMAE* in the brain administered in either form of drugs was gradually phosphorylated to yield DMAE*-P, which was in turn converted to ptd-DMAE*, seemingly the end metabolite of DMAE* in the brain. 3) Acid-soluble and lipid cholines derived from DMAE* and MF (DMAE*) were also found in the brain. However, methylations of DMAE or its ester were attributed to occur in organs other than the brain, such as the liver, as revealed by relative incorporations of a labeled methyl group into lipid choline in the brain and liver after the treatment of methionine-methyl-14C.
Reference: 宮崎亀, et al. “Comparative studies on the metabolism of. BETA.-dimethylaminoethanol in the mouse brain and liver follosing administration of. BETA.-dimethyl-aminoethanol and its p-chlorophenoxyacetate, meclofenoxate.” Chemical and Pharmaceutical Bulletin 24.4 (1976): 763-769.doi.org/10.1248/cpb.24.763
Studies on the origin of choline in the brain of the rat
- Labelled precursors of choline, namely ethanolamine, dimethylaminoethanol and methionine and also labelled choline itself were injected intraperitoneally into the adult female rat and the incorporation into lipids and water-soluble fractions was traced in liver, blood and brain. 2. No significant free choline was detected and no labelling of the phosphorylcholine of blood. There was, however, considerable labelling of the phosphorylcholine of brain and liver. 3. After intracerebral injection, [1,2-14C]dimethylaminoethanol was rapidly phosphorylated and converted into phosphatidyldimethylaminoethanol, presumably by the cytidine pathway. 4. In view of the pattern of labelling and the amount of phosphatidylcholine in the tissues examined, it seems highly likely that choline is transported to the brain by the blood in a lipid-bound form.
Reference: Ansell, G. B., and Sheila Spanner. “Studies on the origin of choline in the brain of the rat.” Biochemical Journal 122.5 (1971): 741-750.DOI: 10.1042/bj1220741
Increases in choline levels in rat brain elicited by meclofenoxate
Meclofenoxate, the p-cholorophenoxyacetic acid ester of deanol, was found to dramatically elevate choline (Ch) levels in the rat CNS. In the hippocampus, this elevation in choline was accompanied by a new elevated steady state level in acetylcholine (ACh). No such coupling was observed in the striatum or parietal cortex. Deanol also elevated choline levels in the CNS but was about half as potent as meclofenoxate; p-chlorophenoxyacetic acid was inactive in this respect. Lesions of striatal neurons with kainic acid and of hippocampal cholinergic nerve endings with surgical section of the fimbria indicated that the changes in choline levels were mainly extraneuronal. In spite of the changes in choline and ACh levels, no consistant alterations in ACh turnover were measured. In summary, meclofenoxate induced dramatic alterations in CNS choline metabolism and may, therefore, be a useful therapeutic tool for potentiating depressed cholinergic neurons.
Reference: Wood, P. L., and Anne Péloquin. “Increases in choline levels in rat brain elicited by meclofenoxate.” Neuropharmacology 21.4 (1982): 349-354.doi:10.1016/0028-3908(82)90099-5
The incorporation of the phosphate esters of N-substituted aminoethanols into the phospholipids of brain and liver
- The phosphate esters of dimethylaminoethanol and monomethylaminoethanol can be incorporated from their cytidine diphosphate esters into the phospholipids of brain and liver dispersions; the deoxycytidine nucleotides of the same bases are less effective precursors. 2. The cytidylyltransferases of brain and liver are less effective in forming the cytidine diphosphate esters of monomethylaminoethanol and dimethylaminoethanol than those of ethanolamine and choline.
Reference: Ansell, G. B., and T. Chojnacki. “The incorporation of the phosphate esters of N-substituted aminoethanols into the phospholipids of brain and liver.” Biochemical Journal 98.1 (1966): 303.
Long term acetyl–L carnitine treatment in Alzheimer’s disease
In a double-blind, placebo-controlled, parallel-group, randomized clinical trial, we studied the efficacy of long-term (1-year) oral treatment with acetyl-L-carnitine in 130 patients with a clinical diagnosis of Alzheimer’s disease. We employed 14 outcome measures to assess functional and cognitive impairment. After 1 year, both the treated and placebo groups worsened, but the treated group showed a slower rate of deterioration in 13 of the 14 outcome measures, reaching statistical significance for the Blessed Dementia Scale, logical intelligence, ideomotor and buccofacial apraxia, and selective attention. Adjusting for initial scores with analysis of covariance, the treated group showed better scores on all outcome measures, reaching statistical significance for the Blessed Dementia Scale, logical intelligence, verbal critical abilities, long-term verbal memory, and selective attention. The analysis for patients with good treatment compliance showed a greater drug benefit than for the overall sample. Reported adverse events were relatively mild, and there was no significant difference between the treated and placebo groups either in incidence or severity.
Reference: Spagnoli, A., et al. “Long term acetyl-L carnitine treatment in Alzheimer’s disease.” Neurology 41.11 (1991): 1726-1726.doi: http://dx.doi.org/10.1212/WNL.41.11.1726
Memory loss in old rats is associated with brain mitochondrial decay and RNA/DNA oxidation: Partial reversal by feeding acetyl-L-carnitine and/or R-α-lipoic acid
Accumulation of oxidative damage to mitochondria, protein, and nucleic acid in the brain may lead to neuronal and cognitive dysfunction. The effects on cognitive function, brain mitochondrial structure, and biomarkers of oxidative damage were studied after feeding old rats two mitochondrial metabolites, acetyl-L-carnitine (ALCAR) [0.5% or 0.2% (wt/vol) in drinking water], and/or R-α-lipoic acid (LA) [0.2% or 0.1% (wt/wt) in diet]. Spatial memory was assessed by using the Morris water maze; temporal memory was tested by using the peak procedure (a time-discrimination procedure). Dietary supplementation with ALCAR and/or LA improved memory, the combination being the most effective for two different tests of spatial memory (P < 0.05; P < 0.01) and for temporal memory (P < 0.05). Immunohistochemical analysis showed that oxidative damage to nucleic acids (8-hydroxyguanosine and 8-hydroxy-2′-deoxyguanosine) increased with age in the hippocampus, a region important for memory. Oxidative damage to nucleic acids occurred predominantly in RNA. Dietary administration of ALCAR and/or LA significantly reduced the extent of oxidized RNA, the combination being the most effective. Electron microscopic studies in the hippocampus showed that ALCAR and/or LA reversed age-associated mitochondrial structural decay. These results suggest that feeding ALCAR and LA to old rats improves performance on memory tasks by lowering oxidative damage and improving mitochondrial function.
Reference: Liu, Jiankang, et al. “Memory loss in old rats is associated with brain mitochondrial decay and RNA/DNA oxidation: partial reversal by feeding acetyl-L-carnitine and/or R-α-lipoic acid.” Proceedings of the National Academy of Sciences 99.4 (2002): 2356-2361.doi: 10.1073/pnas.261709299
A 1-year multicenter placebo-controlled study of acetyl-L-carnitine in patients with Alzheimer’s disease
A 1-year, double-blind, placebo-controlled, randomized, parallel-group study compared the efficacy and safety of acetyl-L-carnitine hydrochloride (ALCAR) with placebo in patients with probable Alzheimer’s disease (AD). Subjects with mild to moderate probable AD, aged 50 or older, were treated with 3 g/day of ALCAR or placebo (1 g tid) for 12 months. Four hundred thirty-one patients entered the study, and 83% completed 1 year of treatment.
The Alzheimer’s Disease Assessment Scale cognitive component and the Clinical Dementia Rating Scale were the primary outcome measures.Overall, both ALCAR- and placebo-treated patients declined at the same rate on all primary and most secondary measures during the trial. In a subanalysis by age that compared early-onset patients (aged 65 years or younger at study entry) with late-onset patients (older than 66 at study entry), we found a trend for early-onset patients on ALCAR to decline more slowly than early-onset AD patients on placebo on both primary endpoints. In addition, early-onset patients tended to decline more rapidly than older patients in the placebo groups. Conversely, late-onset AD patients on ALCAR tended to progress more rapidly than similarly treated early-onset patients. The drug was very well tolerated during the trial.
The study suggests that a subgroup of AD patients aged 65 or younger may benefit from treatment with ALCAR whereas older individuals might do more poorly.However, these preliminary findings are based on post hoc analyses. A prospective trial of ALCAR in younger patients is underway to test the hypothesis that young, rapidly progressing subjects will benefit from ALCAR treatment.
Reference: Liu, Jiankang, et al. “Memory loss in old rats is associated with brain mitochondrial decay and RNA/DNA oxidation: partial reversal by feeding acetyl-L-carnitine and/or R-α-lipoic acid.” Proceedings of the National Academy of Sciences 99.4 (2002): 2356-2361. doi: http://dx.doi.org/10.1212/WNL.47.3.705
Meta-analysis of double blind randomized controlled clinical trials of acetyl-L-carnitine versus placebo in the treatment of mild cognitive impairment and mild Alzheimer’s disease
The efficacy of acetyl-L-carnitine (gamma-trimethyl-β-acetylbutyrobetaine (Alcar) in mild cognitive impairment (MCI) and mild (early) Alzheimer’s disease (AD) was investigated with a meta-analysis of double-blind, placebo-controlled prospective, parallel group comparison studies of at least 3 months duration. The duration of the studies was 3, 6 or 12 months and the daily dose varied between studies from 1.5–3.0 g/day. An effect size was calculated to reflect the results of the variety of measures used in the studies grouped into the categories of clinical tests and psychometric tests. The effect sizes from the categories were integrated into an overall summary effect size. The effect size for the Clinical Global Impression of Change (CGI-CH) was calculated separately. Meta-analysis showed a significant advantage for Alcar compared to placebo for the integrated summary effect [ESall scales=0.201, 95% confidence interval (CI)=0.107–0.295] and CGI-CH (ESCGI-CH=0.32, 95% CI=0.18–0.47). The beneficial effects were seen on both the clinical scales and the psychometric tests. The advantage for Alcar was seen by the time of the first assessment at 3 months and increased over time. Alcar was well tolerated in all studies.
Reference:Montgomery, Stuart A., L. J. Thal, and R. Amrein. “Meta-analysis of double blind randomized controlled clinical trials of acetyl-L-carnitine versus placebo in the treatment of mild cognitive impairment and mild Alzheimer’s disease.” International clinical psychopharmacology 18.2 (2003): 61-71.
A 1-year controlled trial of acetyl-L-carnitine in early-onset AD
Objective: To determine the efficacy of acetyl-L-carnitine (ALCAR) on the rate of decline in early-onset AD patients.
Methods: A 1-year, multicenter, double-blind, placebo-controlled, randomized trial was conducted. Subjects were 45 to 65 years old, with a diagnosis of probable AD according to National Institute of Neurological Communicative Disorders–Alzheimer’s Disease and Related Disorders Association criteria and had a Mini-Mental State Examination (MMSE) score between 12 and 26. They were treated with ALCAR (1 g tid) or placebo. Primary outcome measures were the Alzheimer’s Disease Assessment Scale–Cognitive Component and the Clinical Dementia Rating Scale. Secondary measures included the ADAS Non-Cognitive Subscale, the MMSE, an Activities of Daily Living Scale (ADL), and a Clinician-Based Impression of Change (CIBIC).
Results: Two-hundred twenty-nine patients were enrolled and randomized to drug treatment, with 117 taking placebo and 112 taking ALCAR. There were no significant differences between the two groups at baseline. For the primary outcome measures, there were no significant differences between the treatment groups on the change from baseline to endpoint in the intent-to-treat analysis. In the completer sample only, there was less deterioration in the MMSE for the ALCAR-treated subjects. There was no difference in rate of decline on the CIBIC and the ADL scale. There were no significant differences in the incidence of adverse events by treatment arm.
Conclusion: Overall, in a prospectively performed study in young-onset AD patients, ALCAR failed to slow decline. Less decline was seen on the MMSE in the completer sample only, with the difference being mediated by reducing decline in attention. A combination of ALCAR and a cholinesterase inhibitor should be tested for additivity.
Reference:Thal, L. J., et al. “A 1-year controlled trial of acetyl-l-carnitine in early-onset AD.” Neurology 55.6 (2000): 805-810. doi: http://dx.doi.org/10.1212/WNL.55.6.805
Paclitaxel and Cisplatin-Induced Neurotoxicity
A Protective Role of Acetyl-L-Carnitine
Purpose: Antineoplastic drugs belonging to platinum or taxane families are severely neurotoxic, inducing the onset of disabling peripheral neuropathies with different clinical signs. Acetyl-L-carnitine (ALC) is a natural occurring compound with a neuroprotective activity in several experimental paradigms. In this study we have tested the hypothesis that ALC may have a protective role on cisplatin and paclitaxel-induced neuropathy.
Experimental Design: Sensory nerve conduction velocity (SNCV) was measured in rats before, at end, and after an additional follow-up period from treatments with cisplatin, paclitaxel, or with the respective combination with ALC. In addition, serum from treated animals was collected to measure the levels of circulating NGF, and left sciatic nerves were processed for light and electron microscope observations. ALC interference on cisplatin and paclitaxel antitumor activity and protective mechanisms were investigated using several in vitro and in vivo models.
Results: ALC cotreatment was able to significantly reduce the neurotoxicity of both cisplatin and paclitaxel in rat models, and this effect was correlated with a modulation of the plasma levels of NGF in the cisplatin-treated animals. Moreover, experiments in different tumor systems indicated the lack of interference of ALC in the antitumor effects of cisplatin and paclitaxel. The transcriptional profile of gene expression in PC12 cells indicated that ALC, in the presence of NGF, was able to positively modulate NGFI-A expression, a gene relevant in the rescue from tissue-specific toxicity. Finally, the transcriptionally ALC-mediated effects were correlated to increase histone acetylation.
Conclusion: In conclusion, our results indicate that ALC is a specific protective agent for chemotherapy-induced neuropathy after cisplatin or paclitaxel treatment without showing any interference with the antitumor activity of the drugs.
Reference: Pisano, Claudio, et al. “Paclitaxel and Cisplatin-Induced Neurotoxicity A Protective Role of Acetyl-L-Carnitine.” Clinical Cancer Research 9.15 (2003): 5756-5767.
Clinical and neurochemical effects of acetyl-L-carnitine in Alzheimer’s disease
In a double-blind, placebo study, acetyl-L-carnitine was administered to 7 probable Alzheimer’s disease patients who were then compared by clinical and 31P magnetic resonance spectroscopic measures to 5 placebo-treated probable AD patients and 21 age-matched healthy controls over the course of 1 year. Compared to AD patients on placebo, acetyl-L-carnitine-treated patients showed significantly less deterioration in their Mini-Mental Status and Alzheimer’s Disease Assessment Scale test scores. Furthermore, the decrease in phosphomonoester levels observed in both the acetyl-L-carnitine and placebo AD groups at entry was normalized in the acetyl-L-carnitine-treated but not in the placebo-treated patients. Similar normalization of high-energy phosphate levels was observed in the acetyl-L-carnitine-treated but not in the placebo-treated patients. This is the first direct in vivo demonstration of a beneficial effect of a drug on both clinical and CNS neurochemical parameters in AD.
Reference: Pettegrew, Jay W., et al. “Clinical and neurochemical effects of acetyl-L-carnitine in Alzheimer’s disease.” Neurobiology of aging 16.1 (1995): 1-4. doi:10.1016/0197-4580(95)80001-8
Feeding acetyl-L-carnitine and lipoic acid to old rats significantly improves metabolic function while decreasing oxidative stress
Mitochondrial-supported bioenergetics decline and oxidative stress increases during aging. To address whether the dietary addition of acetyl-L-carnitine [ALCAR, 1.5% (wt/vol) in the drinking water] and/or (R)-α-lipoic acid [LA, 0.5% (wt/wt) in the chow] improved these endpoints, young (2–4 mo) and old (24–28 mo) F344 rats were supplemented for up to 1 mo before death and hepatocyte isolation. ALCAR+LA partially reversed the age-related decline in average mitochondrial membrane potential and significantly increased (P = 0.02) hepatocellular O2 consumption, indicating that mitochondrial-supported cellular metabolism was markedly improved by this feeding regimen. ALCAR+LA also increased ambulatory activity in both young and old rats; moreover, the improvement was significantly greater (P = 0.03) in old versus young animals and also greater when compared with old rats fed ALCAR or LA alone. To determine whether ALCAR+LA also affected indices of oxidative stress, ascorbic acid and markers of lipid peroxidation (malondialdehyde) were monitored. The hepatocellular ascorbate level markedly declined with age (P = 0.003) but was restored to the level seen in young rats when ALCAR+LA was given. The level of malondialdehyde, which was significantly higher (P = 0.0001) in old versus young rats, also declined after ALCAR+LA supplementation and was not significantly different from that of young unsupplemented rats. Feeding ALCAR in combination with LA increased metabolism and lowered oxidative stress more than either compound alone.
Refernce: Hagen, Tory M., et al. “Feeding acetyl-L-carnitine and lipoic acid to old rats significantly improves metabolic function while decreasing oxidative stress.” Proceedings of the National Academy of Sciences 99.4 (2002): 1870-1875.doi: 10.1073/pnas.261708898
Double-blind, placebo controlled study of acetyl-l-carnitine in patients with Alzheimer’s dementia
A randomized, double-blind, placebo-controlled, parallel-group clinical trial was carried out to compare 24-week periods of treatment with I gacetyl-l-carnitine twice daily and placebo in the treatment of patients with dementia of the Alzheimer type. A total of 36 patients entered the trial, of whom 20 patients (7 active, 13 placebo) completed the full 24 weeks. Whilst several of the efficacy indices showed little change in either group during the trial, there was an apparent trend for more improvement in the acetyl-l-carnitine group in relation to the Names Learning Test and a computerized Digit Recall Test, both related to aspects of short-term memory. Similarly, there was a trend for reaction time in the computerized classification test to show less deterioration in the active treatment group. Changes within groups, and changes between groups, failed to reach statistical significance, at least partially because of the small number of patients available for analysis. Two indices of overall therapeutic benefit showed a trend for less deterioration in the active-treatment group than in the placebo group. Nausea and/or vomiting occurred in 5 patients in the acetyl-l-carnitine group. Laboratocy tests revealed no signs of drug toxicity. The results suggest that acetyl-l-carnitine may have a beneficial effect on some clinical features of Alzheimer-type dementia, particularly those related to short-term memory.
Reference: Rai, G., et al. “Double-blind, placebo controlled study of acetyl-l-carnitine in patients with Alzheimer’s dementia.” Current medical research and opinion 11.10 (1990): 638-647.DOI:10.1185/03007999009112690
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