Effects of asiaticoside on cognitive deficits induced by [beta]-amyloid protein in mice

Abstract

Asiaticoside, a main triterpene of Centella asiatica which was well known for wound healing effect. In folk medicine, Centella asiatica has been used as a brain food beneficial for memory and senility with a little supporting evidence by scientific research. Therefore, in the present study, the potential beneficial effect of asiaticoside on learning and memory was investigated by using P-amyloid protein-induced memory impairment in mice injected as an animal testing model. After starting daily oral administration of asiaticoside at doses of 5, 10, 25 and 50 mg/kg/day for 1 week, 9 nmoles of β-amyloid protein fragment 25-35 was intracerebro-ventricularly (i.c.v.) injected in mice to impair learning and memory. A series of cognitive function tests including spontaneous alternation behavior in a Y-maze, performance in a water maze, and passive avoidance tasks were performed, starting 7 days after Aβ 25.35 injection. Measurements of brain lipid peroxidation and total glutathione content, biomarkers of oxidative stress, were done after finishing behavioral tests. The experimental results suggest that asiaticoside at doses of 5, 10 and 25 mg/kg/day effectively prevent Aβ25-35 induced short-term memory deficit in a Y-maze task and long term reference memory deficit in a water maze task without any changes in locomotor and exploratory behaviors. However, asiaticoside administration failed to reveal any beneficial effects on working memory in water maze task and memory retention in a step-through passive avoidance task. Asiaticoside administration also significantly reduced oxidative stress in brains of A β25-35 injected mice. Taken together, these results suggest that asiaticoside may possess a memory enhancing effect for certain forms of cognitive deficit. This beneficial effect may be, at least partly, due to its strong antioxidant property.