Acetylcholinesterase and α-glucosidase inhibitory compounds from Callicarpa maingayi

Abstract

Phytochemical investigation on the soluble fractions of n-hexane and dichloromethane of methanolic leaves extract of the Callicarpa maingayi K. & G. led to the isolation of three triterpenoids [euscaphic acid (1), arjunic acid (2), and ursolic acid (3)] together with two flavones [apigenin (4) and acacetin (5)], two phytosterols [stigmasterol 3-O-β-glycopyranoside (6) and sitosterol 3-O-β-glycopyranoside (7)], and a fatty acid [n-hexacosanoic acid (8)]. Six (6) compounds (1, 2, 3, 4, 5, and 8) are reported for the first time from this species. Their structures were elucidated and identified by extensive NMR techniques, GC-MS and comparison with the previously reported literature. Compound 3 was found to displayed good inhibition against acetylcholinesterase with an IC₅₀ value of 21.5 ± 0.022 μM, while 1 and 2 exhibited pronounced α-glucosidase inhibitory activity with IC₅₀ values of 22.4 ± 0.016 μM and 24.9 ± 0.012 μM, respectively.

Keywords: Callicarpa maingayi; acetylcholinesterase inhibitor; triterpenoids; α-glucosidase inhibitor.