Neuroprotective effect of Alpinia galanga (L.) fractions on Aß(25-35) induced amnesia in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: The rhizomes of Alpinia galanga (L.) Willd (Zingiberaceae), a ginger substitute for flavouring food was traditionally used as nervine tonic and stimulant. AIM OF THE STUDY: This investigation is designed to screen cognitive improvement of Alpinia galanga (AG) fractions in Alzheimer's type of amnesia in mice induced by Aß((25-35)). MATERIALS AND METHODS: Alzheimer's disease induced mice treated with fractions (n-hexane, chloroform and ethyl acetate) of AG in 200 and 400mg/kg. Neurotoxicity was induced by intracerebroventricular injection of Aß((25-35)) on the 14th day of 21 days drug treatment. Open field and water maze were carried to determine habituation memory and hippocampal memory. Na(+)/K(+)-ATPase, acetylcholinesterase (AChE) and antioxidant enzymes (SOD, GPx, catalase and vitamin C) were determined in brain tissue homogenate to estimate the brain biochemical changes and its anti-amnesic potential with intensity of oxidative stress signaling. Further bioactive (chloroform) fraction was eluted through column chromatography to identify the lead molecules. RESULTS: Increased habituation memory and decreased escape latency in behavioral parameter are the indicative of the cognitive enhancement after treatment with Alpinia galanga fractions. Increment in Na(+)/K(+)-ATPase and antioxidant activity depicts brain membrane integrity improvement and free radical scavenging property. AChE level was decreased to improve the cognition by enhancing cholinergic transmission. CONCLUSION: Anti-amnesic effect was exerted by various fractions of Alpinia galanga. Among all fractions, preeminent neuroprotection was exerted by chloroform fraction, which has compound, 1'δ-1'-acetoxyeugenol acetate and it may be a potential therapeutic agent for Alzheimer's type of amnesia. These results further motivate us to explore the activity of lead compound's anti-amnesic effect on transgenic mice model of AD.

Neurotransmitter metabolic enzymes and antioxidant status on Alzheimer's disease induced mice treated with Alpinia galanga (L.) Willd.

Amyloid ß25₋35 (Aß) peptide may be neurotoxic during the progression of Alzheimer's disease by eliciting reactive oxygen species. The use of folklore medicine is prevalent and plants which possess a rejuvenating property are a large source of natural antioxidants that might afford leads for the development of novel drugs in neurodegenerative disorders. The study was designed to investigate the effect of an ethanol extract of Alpinia galanga (L.) Willd (EAG) on oxidative stress induced Alzheimer's type amnesia in mice. Mice were treated with an experimental extract at 200 mg/kg and 400 mg/kg dose for 14 days and injected with neurotoxic Aß and the doses were continued for 21 days. Behavioural studies with open field, step-down inhibitory avoidance and a water maze after treatment indicated the acceleration in cognitive function. The elevated levels of acetylcholinesterase and monoamine oxidase enzymes in amnesia induced mice were attenuated by treatment with EAG. The generation of free radicals was decreased due increased activity of antioxidant enzymes after treatment with EAG. These findings suggested that EAG exerts an antiamnesiac effect in Aß induced neurodegeneration through an antioxidant property.