(+)-alpha-viniferin, a stilbene Trimer from Caragana chamlague inhibits acetylcholinesterase

In the course of screening natural products for anti-acetylcholinesterase (AChE) activity, we found that a total methanolic extract of the underground parts of Caragana chamlague (Leguminosae) had significant inhibition towards AChE. Bioactivity-guided fractionation of the total methanolic extract resulted in the isolation and identification of two active stilbene oligomers, (+)-alpha -viniferin (1) and kobophenol A (2). Both 1 and 2 inhibited AChE activity in a dose-dependent manner, and the IC50 values of I and 2 were 2.0 and 115.8 mum, respectively. The AChE inhibitory activity of I was specific, reversible and noncompetitive.