A new flavonoid from the leaves of Garcinia mckeaniana Craib and alpha-glucosidase and acetylcholinesterase inhibitory activities

From the ethyl acetate extract (EtOAc) of the Vietnamese Garcinia mckeaniana leaves, a new flavone 8-C-glycoside 2'',6''-di-O-acetylvitexin (1), together with six known analogs 2-7 were isolated. Their structures were determined by spectral methods and compared with literature data. In alpha-glucosidase inhibitory assay, the EtOAc extract and its flavone and biflavone derivatives possessed the significant IC50 range of 9.17-97.53 mu M, as compared with that of the positive control acarbose (249 mu M). Flavones and biflavones showed are better than flavone glycosides in both alpha-glucosidase and acetylcholinesterase inhibitory activities