Endogenous bioactive compounds of naked oats (Avena nuda L.) inhibit α-amylase and α-glucosidase activity

Abstract

This study aims to investigate the inhibitory effects of free and bound bioactive extracts from naked oat on amylase and glucosidase activity. The free compound extract mainly included kaempferol-3-O-galactoside-6″-rhamnoside-3‴-rha, hesperetin-7-O-neohesperidoside, ginsenoside Re and soyasaponin Ba. Ten substances were detected in the bound compound extract, including ferulic acid, oxyacanthine, and trans-4-coumaric acid. The free and bound compound extracts showed dose-dependent inhibitory effects on α-amylase and α-glucosidase; the inhibition of α-amylase was reversible anti-competitive inhibition, and the inhibition of α-glucosidase was reversible linear mixed inhibition. The saponin ginsenoside Re had poor inhibitory effects on α-amylase and α-glucosidase; the saponin soyasaponin Ba had a poor inhibitory effect on α-amylase but a good inhibitory effect on α-glucosidase. After adding the extracts to the different starches, the hydrolysis rates all decreased significantly (p < 0.05). This study elucidates the low digestibility of naked oats and will help facilitate the development of low-glycemic foods using naked oats.