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Huperzine A Research
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Novel Anti-Alzheimer's Dimer Bis(7)-Cognitin: Cellular and Molecular Mechanisms of Neuroprotection Through Multiple Targets.
Department of Applied Biology & Chemical Technology, Institute of Modern Chinese Medicine, the Hong Kong Polytechnic University, Hong Kong SAR, China.
Alzheimer's disease (AD) is a progressive and degenerative brain disorder that has emerged as one of the major public health problems in adults. Unfortunately, its molecular pathology and therapeutic strategies remain elusive. Because there are multiple factors closely indicated in the pathogenesis of AD, multiple drug therapy will be required to address the varied pathological aspects of this disease. Existing pharmacological approaches with one-molecule-one-target are limited in their ability to modify the pathology of AD. Novel therapeutics strategies comprise multifunctional compounds specifically designed to target concurrently on different sites at multifactorial etiopathogenesis of AD, thereby providing greater therapeutic efficacy. Over the past decade, our group has developed several series of dimeric acetylcholinesterase (AChE) inhibitors derived from tacrine and huperzine A, a unique anti-Alzheimer's drug originally discovered from a traditional Chinese medicinal plant. Bis(7)-Cognitin, one of our novel dimers, through inhibition of AChE, N-methyl-D-aspartate receptor, nitric oxide synthase, and amyloid precursor protein/beta-amyloid cascade concurrently, possesses remarkable neuroprotective activities. More importantly, the synergism between these targets might serve as one of the most effective therapeutic strategies to arrest/modify pathological process of AD in addition to improving the cognitive functions for AD.
PMID: 19110209
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[+]-Huperzine A treatment protects against N-methyl-D-aspartate-induced seizure/status epilepticus in rats.
Department of Biochemical Pharmacology/Division of Biochemistry, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910-7500, USA.
The toxicity of organophosphorous (OP) nerve agents is attributed to their irreversible inhibition of acetylcholinesterase (AChE), which leads to excessive accumulation of acetylcholine (ACh) and is followed by the release of excitatory amino acids (EAA). EAAs sustain seizure activity and induce neuropathology due to over-stimulation of N-methyl-d-aspartate (NMDA) receptors. Huperzine A (Hup A), a blood-brain barrier permeable selective reversible inhibitor of AChE, has been shown to reduce EAA-induced cell death by interfering with glutamate receptor-gated ion channels in primary neuronal cultures. Although [-]-Hup A, the natural isomer, inhibits AChE approximately 38-fold more potently than [+]-Hup A, both [-]- and [+]-Hup A block the NMDA channel similarly. Here, we evaluated the protective efficacy of [+]-Hup A for NMDA-induced seizure in a rat model. Rats implanted with radiotelemetry probes to record electroencephalography (EEG), electrocardiography (ECG), body temperature, and physical activity were administered various doses of [+]-Hup A (intramuscularly) and treated with 20 microg/kg NMDA (intracerebroventricular) 20-30 min later. For post-exposure, rats were treated with [+]-Hup A (3 mg/kg, intramuscularly) 1 min after NMDA (20 microg/kg). Our data showed that pre- and post-exposure, [+]-Hup A (3 mg/kg) protects animals against NMDA-induced seizures. Also, NMDA-administered animals showed increased survival following [+]-Hup A treatment. [+]-Hup A has no visible effect on EEG, heart-rate, body temperature, or physical activity, indicating a reduced risk of side effects, toxicity, or associated pathology. Our results suggest that [+]-Hup A protects against seizure and status epilepticus (SE) by blocking NMDA-induced excitotoxicity in vivo. We propose that [+]-Hup A, or a unique combination of [+]- and [-]-Hup A, may prove to be effective for pre- and post-exposure treatment of lethal doses of OP-induced neurotoxicity.
PMID: 18588864
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Potential therapeutic targets of huperzine A for Alzheimer's disease and vascular dementia.
State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai, China.
Huperzine A (HupA), a novel Lycopodium alkaloid isolated from Chinese folk medicine Huperzia serrata (Qian Ceng Ta), is a potent, selective and well-tolerated inhibitor of acetylcholinesterase (AChE). It has been proven to significantly improve the learning and memory impairment in Alzheimer's disease (AD) and vascular dementia (VaD) patients in China. Interestingly, our recent data indicate that HupA also possesses other protective functions. This paper will give an overview on the protective effects of HupA, which includes regulating beta-amyloid precursor protein (APP) metabolism, protecting against Abeta-mediated oxidative stress, apoptosis and mitochondrial dysfunction, as well as anti-inflammation. The multiple neuroprotective effects of HupA might yield additional beneficial effects in AD and VaD therapy.
PMID: 18565502
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Huperzine A exhibits anti-inflammatory and neuroprotective effects in a rat model of transient focal cerebral ischemia.
State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Zhangjiang Hi-Tech Park, Shanghai, P.R. China.
Huperzine A, a reversible and selective acetylcholinesterase (AChE) inhibitor, has been reported to display neuroprotective properties. The present study investigated the protective effects of huperzine A in a rat model of transient focal cerebral ischemia created by middle cerebral artery occlusion (MCAO). Huperzine A (0.1 mg/kg), administrated intraperitoneally at the onset of occlusion and 6 h later, markedly restored regional cerebral blood flow, reduced infarct size, and decreased neurological deficit score at 24 h after reperfusion. Along with inhibiting AChE activity, huperzine A inhibited nuclear translocation of transcription factor nuclear factor-kappa B, decreased overexpression of proinflammatory factors in both ipsilateral cortex and striatum, and suppressed activation of glial cells in the ischemic penumbra. Neurological deficit and glial cells activation were also reduced by daily administration of huperzine A for 14 days. Mecamylamine, a nicotinic acetylcholine receptor (nAChR) antagonist, totally abolished the inhibitory effects of huperzine A on ischemia-induced glial cells activation. Meanwhile, mecamylamine partially reversed the infarct size-reducing effects of huperzine A. In conclusion, our results demonstrate that huperzine A exhibits neuroprotective effects against transient focal cerebral ischemia-induced brain injury and suggest that the protection mechanism may involve a cholinergic anti-inflammatory pathway, in which nAChR plays an essential role.
PMID: 18513368
Spirulina Research
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Appraisal of immunomodulatory potential of Spirulina fusiformis: an in vivo and in vitro study.
Faculty of Heath and Life Sciences, Management and Science University, Sekysen 13, 40100, Shah Alam, Selangor Darul Ehsan, Malaysia, mkr474@gmail.com.
In recent years, Spirulina has gained more and more attention from medical scientists as a nutraceutical and a source of potential pharmaceuticals. The present study was conducted to elucidate the immunomodulatory effect of Spirulina fusiformis (a cyanobacterium of the family Oscillatoriaceae) in vivo and in vitro. The in vivo effect of S. fusiformis (400 or 800 mg/kg body wt.) on humoral immune response, cell-mediated immune response and tumour necrosis factor alpha was investigated in mice. We also evaluated the effect of S. fusiformis (50 or 100 mug/ml) in vitro on mitogen (phytohaemagglutinin)-induced T lymphocyte proliferation in heparinized human peripheral blood. For comparison, dexamethasone was used as a standard. In mice, S. fusiformis (400 or 800 mg/kg body wt.) administration significantly inhibited the humoral immune response, cell-mediated immune response (delayed-type hypersensitivity reaction (DTH)) and tumour necrosis factor alpha in a dose-dependent manner. In vitro, S. fusiformis (50 or 100 mug/ml) decreased the mitogen (phytohaemagglutinin)-induced T lymphocyte proliferation in a concentration-dependent manner when compared with control cells. These observations clearly suggest that S. fusiformis has a remarkable immunosuppressive effect, which provides a scientific validation for the popular use of this drug, and helped us in further work on investigating its complete mechanism of action.
PMID: 19093070
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Spirulina in health care management.
School of Studies in Biochemistry and Biotechnology, Jiwaji University, Gwalior-474011, India.
Spirulina is a photosynthetic, filamentous, spiral-shaped and multicellular edible microbe. It is the nature's richest and most complete source of nutrition. Spirulina has a unique blend of nutrients that no single source can offer. The alga contains a wide spectrum of prophylactic and therapeutic nutrients that include B-complex vitamins, minerals, proteins, gamma-linolenic acid and the super anti-oxidants such as beta-carotene, vitamin E, trace elements and a number of unexplored bioactive compounds. Because of its apparent ability to stimulate whole human physiology, Spirulina exhibits therapeutic functions such as antioxidant, anti-bacterial, antiviral, anticancer, anti-inflammatory, anti-allergic and anti-diabetic and plethora of beneficial functions. Spirulina consumption appears to promote the growth of intestinal micro flora as well. The review discusses the potential of Spirulina in health care management.
PMID: 18855693
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Dietary supplementation with blueberries, spinach, or spirulina reduces ischemic brain damage.
National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD 21224, USA.
Free radicals are involved in neurodegenerative disorders, such as ischemia and aging. We have previously demonstrated that treatment with diets enriched with blueberry, spinach, or spirulina have been shown to reduce neurodegenerative changes in aged animals. The purpose of this study was to determine if these diets have neuroprotective effects in focal ischemic brain. Adult male Sprague-Dawley rats were fed with equal amounts of diets (blueberry, spinach, and spirulina) or with control diet. After 4 weeks of feeding, all animals were anesthetized with chloral hydrate. The right middle cerebral artery was ligated with a 10-O suture for 60 min. The ligature was later removed to allow reperfusional injury. Animals were sacrificed and brains were removed for caspase-3 enzymatic assays and triphenyltetrazolium chloride staining at 8 and 48 h after the onset of reperfusion. A subgroup of animals was used for locomotor behavior and biochemical assays. We found that animals which received blueberry, spinach, or spirulina enriched diets had a significant reduction in the volume of infarction in the cerebral cortex and an increase in post-stroke locomotor activity. There was no difference in blood biochemistry, blood CO2, and electrolyte levels among all groups, suggesting that the protection was not indirectly mediated through the changes in physiological functions. Animals treated with blueberry, spinach, or spirulina had significantly lower caspase-3 activity in the ischemic hemisphere. In conclusion, our data suggest that chronic treatment with blueberry, spinach, or spirulina reduces ischemia/reperfusion-induced apoptosis and cerebral infarction.
PMID: 15817266
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Diets enriched in foods with high antioxidant activity reverse age-induced decreases in cerebellar beta-adrenergic function and increases in proinflammatory cytokines.
James A. Haley Veterans Affairs Medical Center, Tampa, Florida 33612, USA.
Antioxidants and diets supplemented with foods high in oxygen radical absorbance capacity (ORAC) reverse age-related decreases in cerebellar beta-adrenergic receptor function. We examined whether this effect was related to the antioxidant capacity of the food supplement and whether an antioxidant-rich diet reduced the levels of proinflammatory cytokines in the cerebellum. Aged male Fischer 344 rats were given apple (5 mg dry weight), spirulina (5 mg), or cucumber (5 mg) either in 0.5 ml water by oral gavage or supplied in the rat chow daily for 14 d. Electrophysiologic techniques revealed a significant decrease in beta-adrenergic receptor function in aged control rats. Spirulina reversed this effect. Apple (a food with intermediate ORAC) had an intermediate effect on cerebellar beta-adrenergic receptor physiology, and cucumber (low ORAC) had no effect, indicating that the reversal of beta-adrenergic receptor function decreases might be related to the ORAC dose. The mRNA of the proinflammatory cytokines tumor necrosis factor-alpha (TNFalpha) and TNFbeta was also examined. RNase protection assays revealed increased levels of these cytokines in the aged cerebellum. Spirulina and apple significantly downregulated this age-related increase in proinflammatory cytokines, whereas cucumber had no effect, suggesting that one mechanism by which these diets work is by modulation of an age-related increase in inflammatory responses. Malondialdehyde (MDA) was measured as a marker of oxidative damage. Apple and spirulina but not cucumber decreased MDA levels in the aged rats. In summary, the improved beta-adrenergic receptor function in aged rats induced by diets rich in antioxidants is related to the ORAC dose, and these diets reduce proinflammatory cytokine levels.
PMID: 12122072
Curcumin Research
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Grape seed polyphenols and curcumin reduce genomic instability events in a transgenic mouse model for Alzheimer's disease.
CSIRO Human Nutrition, PO Box 10041, Adelaide BC, Adelaide, SA 5000, Australia.
The study set out to determine (a) whether DNA damage is elevated in mice that carry mutations in the amyloid precursor protein (APP695swe) and presenilin 1 (PSEN1-dE9) that predispose to Alzheimer's disease (AD) relative to non-transgenic control mice, and (b) whether increasing the intake of dietary polyphenols from curcumin or grape seed extract could reduce genomic instability events in a transgenic mouse model for AD. DNA damage was measured using the micronucleus (MN) assay in both buccal mucosa and erythrocytes and an absolute telomere length assay for both buccal mucosa and olfactory bulb tissue. MN frequency tended to be higher in AD mice in both buccal mucosa (1.7-fold) and polychromatic erythrocytes (1.3-fold) relative to controls. Telomere length was significantly reduced by 91% (p=0.04) and non-significantly reduced by 50% in buccal mucosa and olfactory bulbs respectively in AD mice relative to controls. A significant 10-fold decrease in buccal MN frequency (p=0.01) was found for AD mice fed diets containing curcumin (CUR) or micro-encapsulated grape seed extract (MGSE) and a 7-fold decrease (p=0.02) for AD mice fed unencapsulated grape seed extract (GSE) compared to the AD group on control diet. Similarly, in polychromatic erythrocytes a significant reduction in MN frequency was found for the MGSE cohort (65.3%) (p<0.05), whereas the AD CUR and AD GSE groups were non-significantly reduced by 39.2 and 34.8% respectively compared to the AD Control. A non-significant 2-fold increase in buccal cell telomere length was evident for the CUR, GSE and MGSE groups compared to the AD control group. Olfactory bulb telomere length was found to be non-significantly 2-fold longer in mice fed on the CUR diet compared to controls. These results suggest potential protective effects of polyphenols against genomic instability events in different somatic tissues of a transgenic mouse model for AD.
PMID: 19027755
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Inhibitory effect of curcuminoids on acetylcholinesterase activity and attenuation of scopolamine-induced amnesia may explain medicinal use of turmeric in Alzheimer's disease.
Department of Biological and Biomedical Sciences, The Aga Khan University Medical College, Karachi-74800, Pakistan.
Curcuminoids (a mixture of curcumin, bisdemethoxycurcumin and demethoxycurcumin) share vital pharmacological properties possessed by turmeric, a well known curry spice, considered useful in Alzheimer's disease (AD). The aim of this study was to evaluate if curcuminoids possess acetylcholinesterase (AChE) inhibitory and memory enhancing activities. The in-vitro and ex-vivo models of AChE inhibitory activity were used along with Morris water maze test to study the effect on memory in rats. Curcuminoids inhibited AChE in the in-vitro assay with IC(50) value of 19.67, bisdemethoxycurcumin 16.84, demethoxycurcumin 33.14 and curcumin 67.69 microM. In the ex-vivo AChE assay, curcuminoids and its individual components except curcumin showed dose-dependent (3-10 mg/kg) inhibition in frontal cortex and hippocampus. When studied for their effect on memory at a fixed dose (10 mg/kg), all compounds showed significant (p<0.001) and comparable effect in scopolamine-induced amnesia. These data indicate that curcuminoids and all individual components except curcumin possess pronounced AChE inhibitory activity. Curcumin was relatively weak in the in-vitro assay and without effect in the ex-vivo AChE model, while equally effective in memory enhancing effect, suggestive of additional mechanism(s) involved. Thus curcuminoids mixture might possess better therapeutic profile than curcumin for its medicinal use in AD.
PMID: 18930076
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Curcumin improves learning and memory ability and its neuroprotective mechanism in mice.
Department of Orthopedics, the First Affiliated Hospital, Medical College of Jinan University, Guangzhou, Guangdong, China.
BACKGROUND: Increasing evidence suggests that many neurons may die through apoptosis in Alzheimer's disease (AD). Mitochondrial dysfunction has been implicated in this process of neuronal cell death. One promising approach for preventing AD is based upon anti-apoptosis to decrease death of nerve cells. In this study, we observed the memory improving properties of curcumin in mice and investigated the neuroprotective effect of curcumin in vitro and in vivo. METHODS: The mice were given AlCl(3) orally and injections of D-galactose intraperitoneally for 90 days to establish the AD animal model. From day 45, the curcumin group was treated with curcumin for 45 days. Subsequently, the step-through test, neuropathological changes in the hippocampus and the expression of Bax and Bcl-2 were carried out to evaluate the effect of curcumin on the AD model mice. In cultured PC12 cells, AlCl(3) exposure induced apoptosis. The MTT assay was used to measure cell viabilities; flow cytometric analysis to survey the rate of cell apoptosis; DNA-binding fluorochrome Hoechst 33258 to observe nuclei changes in apoptotic cells and Western blot analysis of Bax, Bcl-2 to investigate the mechanisms by which curcumin protects cells from toxicity. RESULTS: Curcumin significantly improved the memory ability of AD mice in the step-through test, as indicated by the reduced number of step-through errors (P < 0.05) and prolonged step-through latency (P < 0.05). Curcumin also attenuated the neuropathological changes in the hippocampus and inhibited apoptosis accompanied by an increase in Bcl-2 level (P < 0.05), but the activity of Bax did not change (P > 0.05). AlCl(3) significantly reduced the viability of PC12 cells (P < 0.01). Curcumin increased cell viability in the presence of AlCl(3) (P < 0.01). The rate of apoptosis decreased significantly in the curcumin group (P < 0.05) when measured by flow cytometric analysis. Curcumin protected cells by increasing Bcl-2 level (P < 0.05), but the level of Bax did not change (P > 0.05). CONCLUSIONS: This study demonstrates that curcumin improves the memory ability of AD mice and inhibits apoptosis in cultured PC12 cells induced by AlCl(3). Its mechanism may involve enhancing the level of Bcl-2.
PMID: 18701050
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Alzheimer's disease: new diagnostic and therapeutic tools.
Department of Experimental and Applied Pharmacology, University of Pavia, Italy. marco.racchi@unipv.it.
ABSTRACT: On March 19, 2008 a Symposium on Pathophysiology of Ageing and Age-Related diseases was held in Palermo, Italy. Here, the lectures of M. Racchi on History and future perspectives of Alzheimer Biomarkers and of G. Scapagnini on Cellular Stress Response and Brain Ageing are summarized. Alzheimer's disease (AD) is a heterogeneous and progressive neurodegenerative disease, which in Western society mainly accounts for clinica dementia. AD prevention is an important goal of ongoing research. Two objectives must be accomplished to make prevention feasible: i) individuals at high risk of AD need to be identified before the earliest symptoms become evident, by which time extensive neurodegeneration has already occurred and intervention to prevent the disease is likely to be less successful and ii) safe and effective interventions need to be developed that lead to a decrease in expression of this pathology. On the whole, data here reviewed strongly suggest that the measurement of conformationally altered p53 in blood cells has a high ability to discriminate AD cases from normal ageing, Parkinson's disease and other dementias. On the other hand, available data on the involvement of curcumin in restoring cellular homeostasis and rebalancing redox equilibrium, suggest that curcumin might be a useful adjunct in the treatment of neurodegenerative illnesses characterized by inflammation, such as AD.
PMID: 18700965
Cinnamon Research
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Toward prevention of Alzheimers disease--potential nutraceutical strategies for suppressing the production of amyloid beta peptides.
Natural Alternatives International, 1185 Linda Vista Dr., San Marcos, CA 92078, United States. mccarty@pantox.com <mccarty@pantox.com>
Alzheimers disease (AD) can be viewed as a vicious cycle in which excess production and deposition of amyloid beta (Abeta) peptides promote microglial activation, and the resultant production of inflammatory mediators further boosts Abeta production while inducing death and dysfunction of neurons. Abeta production is mediated by beta- and gamma-secretase activities; it is prevented by alpha-secretase activity, and insulin-degrading enzyme (IDE) catabolizes Abeta. High cellular cholesterol content increases Abeta synthesis by boosting beta-secretase activity; inhibition of cholesterol syntheses and/or stimulation of cholesterol export thus diminishes Abeta production. PPARgamma activity decreases Abeta production by promoting harmless catabolism of amyloid precursor protein while blocking the up-regulatory impact of cytokines on beta-secretase expression. Nitric oxide produced by the healthy cerebral microvasculature can suppress Abeta production by boosting expression of alpha-secretase while suppressing that of beta-secretase; conversely, cerebral ischemia provokes increased APP expression. Good insulin sensitivity and efficient brain insulin function protect by inhibiting gamma-secretase activity and increasing expression of IDE. The DHA provided by fish oil diminishes cerebral Abeta deposition in rodent AD models, for unclear reasons. Various measures which oppose microglial activation can inhibit up-regulation of beta-secretase and gamma-secretase by oxidants and cytokines, respectively. These considerations suggest that a number of nutraceutical or lifestyle measures may have potential for preventing or slowing AD: policosanol; 9-cis-beta-carotene; isomerized hops extract; DHA; measures which promote efficient endothelial NO generation, such as low-salt/potassium-rich diets, exercise training, high-dose folate, and flavanol-rich cocoa; chromium picolinate and cinnamon extract as aids for insulin sensitivity; and various agents which can oppose microglial activation, including vitamin D, genistein, and sesamin. The impact of these measures on Abeta production in rodent models of AD should be evaluated, with the intent of defining practical strategies for AD prevention.
PMID: 16828233
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Extract prepared from the bark of Cinnamomum cassia Blume prevents glutamate-induced neuronal death in cultured cerebellar granule cells.
Department of Japanese Oriental Medicine, Faculty of Medicine, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-0194, Japan. shimada@ms.toyama-mpu.ac.jp
We studied the protective effect of a water extract from the bark of Cinnamomum cassia Blume on glutamate-induced neuronal death by MTT assay and its action on (45)Ca(2+) influx using cultured rat cerebellar granule cells. In a dose-dependent manner, this extract (10(-5)-10(-4) g/mL) significantly protected against glutamate-induced cell death and also inhibited glutamate-induced (45)Ca(2+) influx. These results suggest that the bark of Cinnamomum cassia has a protective effect on glutamate-induced neuronal death through the inhibition of Ca(2+) influx. Copyright 2000 John Wiley & Sons, Ltd.
PMID: 10960905
Grean Tea Extract Research
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Natural Antioxidants Protect Neurons in Alzheimer's Disease and Parkinson's Disease.
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Academia Sinica, 15 Datun Road, Chaoyang District, 100101, Beijing, People's Republic of China, zhaobl@sun5.ibp.ac.cn.
"Modern" medicine and pharmacology require an effective medical drug with a single compound for a specific disease. This seams very scientific but usually has unavoidable side effects. For example, the chemical therapy to cancer can totally damage the immunological ability of the patient leading to death early than non-treatment. On the other hand, natural antioxidant drugs not only can cure the disease but also can enhance the immunological ability of the patient leading to healthier though they usually have several compounds or a mixture. For the degenerative disease such as Alzheimer's disease (AD) and Parkinson's disease (PD), natural antioxidant drugs are suitable drugs, because the pathogenesis of these diseases is complex with many targets and pathways. These effects are more evidence when the clinic trial is for long term treatment. The author reviews the studies on the protecting effects of natural antioxidants on neurons in neurodegenerative diseases, especially summarized the results about protective effect of green tea polyphenols on neurons against apoptosis of cellular and animal PD models, and of genestine and nicotine on neurons against Abeta-induced apoptosis of hippocampal neuronal and transgenic mouse AD models.
PMID: 19125328
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Simultaneous manipulation of multiple brain targets by green tea catechins: a potential neuroprotective strategy for Alzheimer and Parkinson diseases.
Eve Topf Center for Neurodegenerative Diseases Research and Department of Pharmacology, Faculty of Medicine, Technion, Haifa, Israel. mandel@tx.technion.ac.il
Current therapeutic approaches for Alzheimer and Parkinson disease (AD and PD, respectively) are merely symptomatic, intended for the treatment of symptoms, but offer only partial benefit, without any disease-modifying activity. Novel promising strategies suggest the use of antiinflammatory drugs, antioxidants, iron-complexing molecules, neurotrophic factor delivery, inhibitors of the amyloid precursor protein (APP)-processing secretases, gamma and beta (that generate the amyloid-beta peptides, Abeta), anti-Abeta aggregation molecules, the interference with lipid cholesterol metabolism and naturally occurring plant flavonoids to potentially reverse the course of the diseases. Human epidemiological and new animal data suggest that tea drinking may decrease the incidence of dementia, AD, and PD. In particular, its main catechin polyphenol constituent (-)-epigallocatechin-3-gallate (EGCG) has been shown to exert neuroprotective/neurorescue activities in a wide array of cellular and animal models of neurological disorders. In the current article, we review the literature on the impact of the multimodal activities of green tea polyphenols and their neuroprotective effect on AD and PD.
PMID: 19040558
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Cell signaling pathways and iron chelation in the neurorestorative activity of green tea polyphenols: special reference to epigallocatechin gallate (EGCG).
Eve Topf Center for Neurodegenerative Diseases Research and Department of Pharmacology, Faculty of Medicine, Technion, Haifa, Israel. mandel@tx.technion.ac.il
Although much progress has been made in understanding the pathogenesis of Alzheimer's disease (AD), the current therapeutic approaches are merely symptomatic, intended for the treatment of cognitive symptoms, such as disturbances in memory and perception. Novel promising strategies suggest the use of anti-inflammatory drugs, antioxidants including natural occurring plant flavonoids, iron-complexing molecules, neurotrophic factor delivery, inhibitors of the amyloid-beta protein precursor processing secretases, gamma and beta, that generate amyloid-beta peptides and the interference with lipid and cholesterol metabolism. Human epidemiological and new animal data suggest that tea drinking may decrease the incidence of dementia, AD and Parkinson's disease. In particular, its main catechin polyphenol constituent (-)-epigallocatechin-3-gallate (EGCG) has been shown to exert neuroprotective/neurorescue activities in a wide array of cellular and animal models of neurological disorders. This review provides a detailed overview on the multimodal activities of green tea polyphenols with emphasis on their iron chelating, neurorescue/neuroregenerative and mitochondrial stabilization action.
PMID: 18953110
1: J Nutr. 2008 Aug;138(8):1578S-1583S.
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Targeting multiple neurodegenerative diseases etiologies with multimodal-acting green tea catechins.
Eve Topf Center for Neurodegenerative Diseases Research and Department of Pharmacology, Faculty of Medicine, Technion, Haifa, Israel. mandel@tx.technion.ac.il
Green tea is currently considered a source of dietary constituents endowed with biological and pharmacological activities relevant to human health. Human epidemiological and new animal data suggest that the pharmacological benefits of tea drinking may help to protect the brain as we age. Indeed, tea consumption is inversely correlated with the incidence of dementia and Alzheimer's and Parkinson's diseases. In particular, its main catechin polyphenol constituent (-)-epigallocatechin-3-gallate has been shown to exert neuroprotective/neurorescue activities in a wide array of cellular and animal models of neurological disorders. The intense efforts dedicated in recent years to shed light on the molecular mechanisms participating in the brain protective action of green tea indicate that in addition to the known antioxidant activity of catechins, the modulation of signal transduction pathways, cell survival/death genes, and mitochondrial function all contribute significantly to the induction of neuron viability. Because of the multietiological character of neurodegenerative disease pathology, these natural compounds are receiving significant attention as therapeutic cytoprotective agents that simultaneously manipulate multiple desired targets in the central nervous system. This article elaborates on the multimodal activities of green tea polyphenols with emphasis on their recently described neurorescue/neuroregenerative and mitochondrial stabilization actions.
PMID: 18641210
1: Brain Res. 2008 Jun 12;1214:177-87. Epub 2008 Apr 7.
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Green tea epigallocatechin-3-gallate (EGCG) reduces beta-amyloid mediated cognitive impairment and modulates tau pathology in Alzheimer transgenic mice.
Rashid Laboratory for Developmental Neurobiology, Silver Child Development Center, Department of Psychiatry and Behavioral Medicine, and Department of Neurosurgery, University of South Florida, Tampa, FL 33613, USA.
We previously reported that intraperitoneal (i.p.) injection (20 mg/kg) of (-)-epigallocatechin-3-gallate (EGCG), the main polyphenolic constituent of green tea, decreased beta-amyloid (Abeta) levels and plaques via promotion of the non-amyloidogenic alpha-secretase proteolytic pathway in "Swedish" mutant amyloid precursor protein overexpressing (APPsw, Tg) mice. Here, we find that EGCG administered orally in drinking water (50 mg/kg) similarly reduces Abeta deposition in these mice. Following a six month treatment of an 8 month old cohort, immunohistochemical analysis of coronal sections reveals that plaque burdens were reduced in the cingulate cortex, hippocampus, and entorhinal cortex by 54%, 43%, and 51%, respectively. Congo red plaque burdens were decreased in the cingulate cortex, hippocampus, and entorhinal cortex by 53%, 53%, and 58%, respectively as well. ELISA of brain homogenates of the treatment Tg mice revealed consistent reductions in both Abeta1-40 and 1-42 soluble and insoluble forms. In the present study we also investigated the effect EGCG administration had on tau pathology and cognition in Tg mice. Both i.p. and orally-treated Tg animals were found to have modulated tau profiles, with markedly suppressed sarkosyl-soluble phosphorylated tau isoforms. Radial arm water maze (RAWM) testing for working memory indicated that EGCG provided cognitive benefit to Tg mice with both i.p. and oral administration, although i.p.-treated animals showed a more pronounced benefit because of the greater impairment of their Tg controls at the time of testing. Taken together, these data further the notion of EGCG dietary supplementation as a potentially safe and effective prophylaxis for Alzheimer's disease.
PMID: 18457818
Resveratrol Research
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Therapeutic potential of resveratrol in Alzheimer's disease.
Litwin-Zucker Research Center for the Study of Alzheimer's Disease, The Feinstein Institute for Medical Research, North Shore-LIJ, Manhasset, NY 11030, USA. vdidier@nshs.edu
Several epidemiological studies indicate that moderate consumption of red wine is associated with a lower incidence of dementia and Alzheimer's disease. Red wine is enriched in antioxidant polyphenols with potential neuroprotective activities. Despite scepticism concerning the bioavailability of these polyphenols, in vivo data have clearly demonstrated the neuroprotective properties of the naturally occurring polyphenol resveratrol in rodent models for stress and diseases. Furthermore, recent work in cell cultures and animal models has shed light on the molecular mechanisms potentially involved in the beneficial effects of resveratrol intake against the neurodegenerative process in Alzheimer's disease.
PMID: 19090994
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Cellular stress response: a novel target for chemoprevention and nutritional neuroprotection in aging, neurodegenerative disorders and longevity.
Calabrese V, Cornelius C, Mancuso C, Pennisi G, Calafato S, Bellia F, Bates TE, Giuffrida Stella AM, Schapira T, Dinkova Kostova AT, Rizzarelli E.
Section of Biochemistry and Molecular Biology, Department of Chemistry, Faculty of Medicine, University of Catania, Viale Andrea Doria 6, 95100, Catania, Italy. calabres@unict.it
The predominant molecular symptom of aging is the accumulation of altered gene products. Moreover, several conditions including protein, lipid or glucose oxidation disrupt redox homeostasis and lead to accumulation of unfolded or misfolded proteins in the aging brain. Alzheimer's and Parkinson's diseases or Friedreich ataxia are neurological diseases sharing, as a common denominator, production of abnormal proteins, mitochondrial dysfunction and oxidative stress, which contribute to the pathogenesis of these so called "protein conformational diseases". The central nervous system has evolved the conserved mechanism of unfolded protein response to cope with the accumulation of misfolded proteins. As one of the main intracellular redox systems involved in neuroprotection, the vitagene system is emerging as a neurohormetic potential target for novel cytoprotective interventions. Vitagenes encode for cytoprotective heat shock proteins (Hsp) Hsp70 and heme oxygenase-1, as well as thioredoxin reductase and sirtuins. Nutritional studies show that ageing in animals can be significantly influenced by dietary restriction. Thus, the impact of dietary factors on health and longevity is an increasingly appreciated area of research. Reducing energy intake by controlled caloric restriction or intermittent fasting increases lifespan and protects various tissues against disease. Genetics has revealed that ageing may be controlled by changes in intracellular NAD/NADH ratio regulating sirtuin, a group of proteins linked to aging, metabolism and stress tolerance in several organisms. Recent findings suggest that several phytochemicals exhibit biphasic dose responses on cells with low doses activating signaling pathways that result in increased expression of vitagenes encoding survival proteins, as in the case of the Keap1/Nrf2/ARE pathway activated by curcumin and NAD/NADH-sirtuin-1 activated by resveratrol. Consistently, the neuroprotective roles of dietary antioxidants including curcumin, acetyl-L-carnitine and carnosine have been demonstrated through the activation of these redox-sensitive intracellular pathways. Although the notion that stress proteins are neuroprotective is broadly accepted, still much work needs to be done in order to associate neuroprotection with specific pattern of stress responses. In this review the importance of vitagenes in the cellular stress response and the potential use of dietary antioxidants in the prevention and treatment of neurodegenerative disorders is discussed.
PMID: 18629638
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Benefits from dietary polyphenols for brain aging and Alzheimer's disease.
Department of Biology, Tor Vergata University of Rome, Via della Ricerca Scientifica, 1, 00133, Rome, Italy. luisa.rossi@uniroma2.it
Brain aging and the most diffused neurodegenerative diseases of the elderly are characterized by oxidative damage, redox metals homeostasis impairment and inflammation. Food polyphenols can counteract these alterations in vitro and are therefore suggested to have potential anti-aging and brain-protective activities, as also indicated by the results of some epidemiological studies. Despite the huge and increasing amount of the in vitro studies trying to unravel the mechanisms of action of dietary polyphenols, the research in this field is still incomplete, and questions about bioavailability, biotransformation, synergism with other dietary factors, mechanisms of the antioxidant activity, risks inherent to their possible pro-oxidant activities are still unanswered. Most of all, the capacity of the majority of these compounds to cross the blood-brain barrier and reach brain is still unknown. This commentary discusses recent data on these aspects, particularly focusing on effects of curcumin, resveratrol and catechins on Alzheimer's disease.
PMID: 18415677
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Dietary supplementation with resveratrol reduces plaque pathology in a transgenic model of Alzheimer's disease.
Department of Neurology and Neurosciences, Weill Medical College of Cornell University, Burke Medical Research Institute, 785 Mamaroneck Ave., White Plains, NY 10605, United States.
Resveratrol, a polyphenol found in red wine, peanuts, soy beans, and pomegranates, possesses a wide range of biological effects. Since resveratrol's properties seem ideal for treating neurodegenerative diseases, its ability to diminish amyloid plaques was tested. Mice were fed clinically feasible dosages of resveratrol for forty-five days. Neither resveratrol nor its conjugated metabolites were detectable in brain. Nevertheless, resveratrol diminished plaque formation in a region specific manner. The largest reductions in the percent area occupied by plaques were observed in medial cortex (-48%), striatum (-89%) and hypothalamus (-90%). The changes occurred without detectable activation of SIRT-1 or alterations in APP processing. However, brain glutathione declined 21% and brain cysteine increased 54%. The increased cysteine and decreased glutathione may be linked to the diminished plaque formation. This study supports the concept that onset of neurodegenerative disease may be delayed or mitigated with use of dietary chemo-preventive agents that protect against beta-amyloid plaque formation and oxidative stress.
PMID: 19041676
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Resveratrol: a natural compound with pharmacological potential in neurodegenerative diseases.
Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados, Sede Sur, México, D.F., Mexico.
Resveratrol is a phytoalexin structurally related to stilbenes, which is synthesized in considerable amounts in the skin of grapes, raspberries, mulberries, pistachios and peanuts, and by at least 72 medicinal and edible plant species in response to stress conditions. It was isolated in 1940 and did not maintain much interest for around five decades until its role in treatment of cardiovascular diseases was suggested. To date, resveratrol has been identified as an agent that may be useful to treat cancer, pain, inflammation, tissue injury, and other diseases. However, currently the attention is being focused in analyzing its properties against neurodegenerative diseases and as antiaging compound. It has been reported that resveratrol shows effects in in vitro models of epilepsy, Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and nerve injury. However, evidences in vivo as well as in human beings are still lacking. Thus, further investigations on the pharmacological effects of resveratrol in vivo are necessary before any conclusions on its effects on neurodegenerative diseases can be obtained.
PMID: 18684235
Coconut Oil Research (MCT)
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Effects of beta-hydroxybutyrate on cognition in memory-impaired adults.
Accera, Inc., Aurora, CO 80010, USA.
Glucose is the brain's principal energy substrate. In Alzheimer's disease (AD), there appears to be a pathological decrease in the brain's ability to use glucose. Neurobiological evidence suggests that ketone bodies are an effective alternative energy substrate for the brain. Elevation of plasma ketone body levels through an oral dose of medium chain triglycerides (MCTs) may improve cognitive functioning in older adults with memory disorders. On separate days, 20 subjects with AD or mild cognitive impairment consumed a drink containing emulsified MCTs or placebo. Significant increases in levels of the ketone body beta-hydroxybutyrate (beta-OHB) were observed 90 min after treatment (P=0.007) when cognitive tests were administered. beta-OHB elevations were moderated by apolipoprotein E (APOE) genotype (P=0.036). For 4+ subjects, beta-OHB levels continued to rise between the 90 and 120 min blood draws in the treatment condition, while the beta-OHB levels of 4- subjects held constant (P<0.009). On cognitive testing, MCT treatment facilitated performance on the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog) for 4- subjects, but not for 4+ subjects (P=0.04). Higher ketone values were associated with greater improvement in paragraph recall with MCT treatment relative to placebo across all subjects (P=0.02). Additional research is warranted to determine the therapeutic benefits of MCTs for patients with AD and how APOE-4 status may mediate beta-OHB efficacy.
PMID: 15123336
1: Brain Res. 2008 Aug 21;1226:209-17. Epub 2008 Jun 11.
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Induction of ketosis may improve mitochondrial function and decrease steady-state amyloid-beta precursor protein (APP) levels in the aged dog.
Department of Pharmacology, University of Toronto, Canada.
Region specific declines in the cerebral glucose metabolism are an early and progressive feature of Alzheimer's disease (AD). Such declines occur pre-symptomatically and offer a potential point of intervention in developing AD therapeutics. Medium chain triglycerides (MCTs), which are rapidly converted to ketone bodies, were tested for their ability to provide an alternate energy source to neurons suffering from compromised glucose metabolism. The present study determined the short-term effects of ketosis in aged dogs, a natural model of amyloidosis. The animals were administered a 2 g/kg/day dose of MCTs for 2 months. Mitochondrial function and oxidative damage assays were then conducted on the frontal and parietal lobes. Amyloid-beta (Abeta), amyloid precursor protein (APP) processing and beta-site APP cleaving enzyme (BACE1) assays were conducted on the frontal, parietal and occipital lobes. Aged dogs receiving MCTs, as compared to age-matched controls, showed dramatically improved mitochondrial function, as evidenced by increased active respiration rates. This effect was most prominent in the parietal lobe. The improved mitochondrial function may have been due to a decrease in oxidative damage, which was limited to the mitochondrial fraction. Steady-state APP levels were also decreased in the parietal lobe after short-term MCT administration. Finally, there was a trend towards a decrease in total Abeta levels in the parietal lobe. BACE1 levels remained unchanged. Combined, these findings suggest that short-term MCT administration improves energy metabolism and decreases APP levels in the aged dog brain.
PMID: 18582445
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Direct assessments of the antioxidant effects of propofol medium chain triglyceride/long chain triglyceride on the brain of stroke-prone spontaneously hypertensive rats using electron spin resonance spectroscopy.
Department of Clinical Care Medicine, Division of Anesthesiology, Kanagawa Dental College, Yokosuka, Kanagawa, Japan.
BACKGROUND: Antioxidant anesthetics such as propofol (2,6-diisopropylphenol) directly inhibit lipid peroxidation via the generation of reactive oxygen species. Currently, there are no other studies regarding the direct effects of propofol medium chain triglyceride/long chain triglyceride (MCT/LCT) on reactive oxygen species generation or in experimental models of reactive oxygen species-induced oxidative stress in the brain. METHODS: The authors investigated the effects of propofol MCT/LCT on reactive oxygen species (hydroxyl radical or superoxide) by electron spin resonance spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide. The effects of propofol MCT/LCT on oxidative stress in the brain of Wistar-Kyoto rats or stroke-prone spontaneously hypertensive rats were investigated by using an in vivo L-band electron spin resonance system to monitor the decay rate of 3-methoxycarbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl as a nitroxyl spin probe. RESULTS: These studies provided direct evidence that propofol MCT/LCT inhibited hydroxyl radical generation, but not superoxide generation. Regarding the hydroxyl radical from the Fenton system, it is likely to be due to the scavenging effects of vehicle. Anesthesia with propofol MCT/LCT reduced the degree of the high oxidative stress in the brain of stroke-prone spontaneously hypertensive rats. CONCLUSION: The current data show that propofol, mixed with clinical reagents (propofol MCT/LCT), resulted in the down-regulation of high oxidative stress due to scavenging hydroxyl radical, as demonstrated by in vitro or in vivo electron spin resonance analysis. These results led to reduced levels of hydroxyl radical, formed by brain injury such as stroke, and may therefore provide advantages for neuroprotection during anesthesia for craniotomy, e.g., in cases of brain disease.
PMID: 18719440
1: Brain Res. 2008 Aug 21;1226:209-17. Epub 2008 Jun 11.
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Induction of ketosis may improve mitochondrial function and decrease steady-state amyloid-beta precursor protein (APP) levels in the aged dog.
Department of Pharmacology, University of Toronto, Canada.
Region specific declines in the cerebral glucose metabolism are an early and progressive feature of Alzheimer's disease (AD). Such declines occur pre-symptomatically and offer a potential point of intervention in developing AD therapeutics. Medium chain triglycerides (MCTs), which are rapidly converted to ketone bodies, were tested for their ability to provide an alternate energy source to neurons suffering from compromised glucose metabolism. The present study determined the short-term effects of ketosis in aged dogs, a natural model of amyloidosis. The animals were administered a 2 g/kg/day dose of MCTs for 2 months. Mitochondrial function and oxidative damage assays were then conducted on the frontal and parietal lobes. Amyloid-beta (Abeta), amyloid precursor protein (APP) processing and beta-site APP cleaving enzyme (BACE1) assays were conducted on the frontal, parietal and occipital lobes. Aged dogs receiving MCTs, as compared to age-matched controls, showed dramatically improved mitochondrial function, as evidenced by increased active respiration rates. This effect was most prominent in the parietal lobe. The improved mitochondrial function may have been due to a decrease in oxidative damage, which was limited to the mitochondrial fraction. Steady-state APP levels were also decreased in the parietal lobe after short-term MCT administration. Finally, there was a trend towards a decrease in total Abeta levels in the parietal lobe. BACE1 levels remained unchanged. Combined, these findings suggest that short-term MCT administration improves energy metabolism and decreases APP levels in the aged dog brain.
PMID: 18582445
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Effects of beta-hydroxybutyrate on cognition in memory-impaired adults.
Accera, Inc., Aurora, CO 80010, USA.
Glucose is the brain's principal energy substrate. In Alzheimer's disease (AD), there appears to be a pathological decrease in the brain's ability to use glucose. Neurobiological evidence suggests that ketone bodies are an effective alternative energy substrate for the brain. Elevation of plasma ketone body levels through an oral dose of medium chain triglycerides (MCTs) may improve cognitive functioning in older adults with memory disorders. On separate days, 20 subjects with AD or mild cognitive impairment consumed a drink containing emulsified MCTs or placebo. Significant increases in levels of the ketone body beta-hydroxybutyrate (beta-OHB) were observed 90 min after treatment (P=0.007) when cognitive tests were administered. beta-OHB elevations were moderated by apolipoprotein E (APOE) genotype (P=0.036). For 4+ subjects, beta-OHB levels continued to rise between the 90 and 120 min blood draws in the treatment condition, while the beta-OHB levels of 4- subjects held constant (P<0.009). On cognitive testing, MCT treatment facilitated performance on the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog) for 4- subjects, but not for 4+ subjects (P=0.04). Higher ketone values were associated with greater improvement in paragraph recall with MCT treatment relative to placebo across all subjects (P=0.02). Additional research is warranted to determine the therapeutic benefits of MCTs for patients with AD and how APOE-4 status may mediate beta-OHB efficacy.
PMID: 15123336
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