α-Glucosidase inhibitory constituents from duranta repens

Abstract

Three C-alkylated flavonoids 7-O-α-D-glucopyranosyl-3,5-dihydroxy- 3′-(4″-acetoxyl-3″-methylbutyl)-6,4′-dimethoxyflavone (1), 7-O-α-D-glucopyranosyl-3,4′-dihydroxy-3′-(4″- acetoxyl-3″-methylbutyl)-5,6-dimethoxy-flavone (2), 3,7,4′- trihydroxy-3′-(8″-acetoxy-7″-methyloctyl)-5, 6-dimethoxyflavone (3) and a trans-clerodane type diterpenoid (-)-6β-hydroxy-5β,8β,9β,10α-cleroda-3,13-dien-16, 15-olid-18-oic acid (4) are reported from Duranta repens along with (+)-hardwickiic acid (5) and (+)-3,13-clerodadien-16,15-olid-18-oic acid (6), isolated for the first time from this species. Their structures were established on the basis of the spectral methods, especially two dimensional (2D) NMR spectroscopy. © 2004 Pharmaceutical Society of Japan.