X-ray crystalographic data, absolute configuration, and anticholinesterase effect of dihydromyricitrin 3-O-rhamnoside

Based on our continuous effort to investigate chemistry and biology of the plant secondary metabolites, we were able to isolate a glycosidal flavonoid 1 from the Wild Egyptian Artichoke. The activity of dihydromyricetin 3-O-rhamnoside (sin. dihydromyricitrin, ampelopsin 3-O-rhamnoside) (1) against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE); its absolute configuration using X-ray crystallography were determined for the first time. Inhibitory activity of 1 against AChE and BChE enzymes were determined using a slightly modified version of Ellman's method. Compound 1 was revealed to have a potent inhibition against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with IC50 values of 0.070 +/- 0.008 and 0.071 +/- 0.004 mM, respectively, where IC50 values of the reference drug (galanthamine) were 0.023 +/- 0.15 and 0.047 +/- 0.91 mM. Compound 1 could be a promising molecule against Alzheimer's disease.