6-Hydroxyflavonoids as α-glucosidase inhibitors from marjoram (origanum majorana) leaves

Abstract

A methanol extract of marjoram leaves strongly inhibited rat intestinal α-glucosidase. Five 6-hydroxyflavonoids, 6-hydroxyapigenin (scutellarein; IC50for sucrose hydrolysis by rat intestinal α-glucosidase, 12 μM), 6-hydroxyapigenin-7-O-β-D-glucopyranoside (>500 μM), 6-hydroxyluteolin-7-O-β-D-glucopyranoside (300 μM), 6-hydroxyapigenin-7-O-(6-O-feruloyl)-β-D-glucopyranoside (>500 μM), and 6-hydroxyluteolin-7-O-(6-O-feruloyl)-β-D-glucopyranoside (>500 μM), were isolated as active principles and related compounds. The two feruloylglucosides are novel compounds. © 2003 by Japan Society for Bioscience, Biotechnology, and Agrochemistry.