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Terminalia chebula Retz. (Combretaceae) is a traditional herbal medicine that is widely used in the treatment of diabetes, immunodeficiency diseases, and stomach ulcer in Asia. However, the anti-amnesic effect of T. chebula has not yet been investigated. The present study was designed to determine whether T. chebula extract (TCE) alleviates amnesia induced by scopolamine in mice. We also investigated possible mechanisms associated with cholinergic system and anti-oxidant effects.
TCE (100 or 200 mg/kg) was orally administered to mice for fourteen days (days 1–14), and scopolamine was intraperitoneally injected to induce memory impairment for seven days (days 8–14). Learning and memory status were evaluated using the Morris water maze. Hippocampal levels of acetylcholine (ACh), acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) were measured ex vivo. Levels of reactive oxygen species (ROS), nitric oxide (NO), and malondialdehyde (MDA) in the hippocampus were also examined.
In the Morris water maze task, TCE treatment reversed scopolamine-induced learning and memory deficits in acquisition and retention. TCE reduced hippocampal AChE activities and increased ChAT and ACh levels in the scopolamine-induced model. Moreover, TCE treatment suppressed scopolamine-induced oxidative damage by ameliorating the increased levels of ROS, NO, and MDA.
These findings suggest that TCE exerts potent anti-amnesic effects via cholinergic modulation and anti-oxidant activity, thus providing evidence for its potential as a cognitive enhancer for amnesia.