CONSTITUENTS ISOLATED FROM THE LEAVES OF RINOREA BENGALENSIS AND THEIR α-GLUCOSIDASE INHIBITORY EFFECTS

Tóm tắt

Phytochemical investigation of the ethanolic extract of Rinorea bengalensis (Wall.) Kuntze leaves led to the isolation of five compounds (1‒5), using various chromatographic separations. Their structures were elucidated to be 4-C-β-D-glucopyranosyl-3,5-dihydroxy-2-methoxybenzamide (1), bergenin (2), kaempferol 3-O-β-D-glucopyranosyl-(1'''→2'')-O-α-L-arabinopyranoside (3), (7α,8α)-dihydrodehyrodiconiferyl alcohol-9-O-β-D-glucopyranoside (4), and (+)-lariciresinol (5) by detailed analysis of 1D and 2D NMR and MS spectroscopic data as well as comparison with those reported. In the in vitro α-glucosidase inhibition assay, compounds 1, 4, and 5 showed inhibitory activity with IC₅₀ values ranging from 11.57 ± 0.76 to 69.98 ± 1.36 μM. Enzyme kinetic analysis revealed that compound 1 behaved as a mixed-type inhibitor with a K_i value of 21.37 ± 0.08 μM. This is the first time that chemical constituents from R. bengalensis and their α-glucosidase inhibitory effect were reported.