Tannoid principles of Emblica officinalis attenuated aluminum chloride induced apoptosis by suppressing oxidative stress and tau pathology via Akt/GSK-3ßsignaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Fruits of Phyllanthus emblica Linn. or Emblica officinalis Gaertn. (Phyllanthaceae) are used in Ayurveda, Siddha, Unani, Arabic, Tibetan and various other folk medicinal systems to promote intelligence and memory. Recent study from our lab indicated the neuroprotective effect of tannoids principles of Emblica officinalis (EoT) against memory loss caused by aluminum chloride (AlCl3) intoxication through attenuating acetylcholine esterase activity and the expression of amyloid ß protein biosynthesis related markers. However the molecular mechanism of EoT has not yet been fully elucidated. AIM OF THE STUDY: The aim of the present study was to further investigate the neuroprotective mechanisms of EoT against AlCl3-induced cognitive deficits, tau hyperphosphorylation, oxidative stress and apoptosis. MATERIALS AND METHODS: Rats were treated with AlCl3 for 60 days to induce biochemical and physiological abnormalities similar to AD patients. AD rats were treated with EoT (100mg/kg., bw. oral) for 60 days. For the examination of neuroprotective effect of EoT, behavior analysis, biochemical estimations and western blot were performed in the hippocampus and cortex of control, EoT treated and untreated AD rats. RESULTS: Intraperitoneal injections of AlCl3 (100mg/kg., b.w.) for 60 days enhanced the learning and memory deficits, levels of TBARS and diminished the levels of reduced glutathione and activities of enzymatic antioxidants as compared to control group. Moreover toxicity of AlCl3 is accompanied by the enhanced expressions of Bax, caspases-3,-9, cytosolic cytochrome c (cyto c), and pTau along with diminished expressions of Bcl-2, mitochondrial cyto c, pGSK-3ß and pAkt. Coadministration of EoT nullified the cognitive deficits, biochemical abnormalities and apoptosis induced by AlCl3 treatment. Moreover EoT prevents tau hyperphosphorylation by targeting the GSK-3ß/Akt signaling pathway. CONCLUSIONS: This study confirms that EoT would be used as a potential drug candidate for AD and other tau pathology-related neuronal degenerative diseases.

Tannoid principles of Emblica officinalis renovate cognitive deficits and attenuate amyloid pathologies against aluminum chloride induced rat model of Alzheimer's disease.

BACKGROUND/AIMS: Emblica officinalis is mentioned as a maharasayana in many Ayurvedic texts and promotes intelligence, memory, freedom from disease, longevity, and strength of the senses. The present study has been designed to explore the memory-enhancing effect of the tannoid principles of E. officinalis (EoT) at the biochemical, anatomical, behavioral, and molecular levels against aluminum chloride (AlCl3) induced Alzheimer's disease (AD) in rats. Aluminum is reported to have an important role in the etiology, pathogenesis, and development of AD. METHODS: Male Wistar rats were divided into control, AlCl3 treated, AlCl3 and EoT (50, 100, and 200 mg/kg bw) co-treated, and EoT (200 mg/kg bw) alone treated groups. In control and experimental rats, behavior tests including water maze and open field test, estimation of aluminum, assay of acetylcholinesterase (AChE) activity, and expression of amyloidogenic proteins were performed. RESULTS: Intraperitonial injection of AlCl3 (100 mg/kg bw) for 60 days significantly elevated the concentration of aluminum (Al), activity of AChE and protein expressions of amyloid precursor protein, A-beta1-42, beta-, and gamma-secretases as compared to control group in hippocampus and cortex. Co-administration of EoT orally to AlCl3 rats for 60 days significantly revert back the Al concentration, AChE activity, and A-beta synthesis-related molecules in the studied brain regions. The spatial learning, memory, and locomotor impairments observed in AlCl3 treated rats were significantly attenuated by EoT. CONCLUSION: Therefore, EoT may be a promising therapy in ameliorating neurotoxicity of aluminum, however further studies are warranted to elucidate the exact mechanism of action of EoT.