Effects of simulated gastrointestinal digestion in vitro on the chemical properties, antioxidant activity, α-amylase and α-glucosidase inhibitory activity of polysaccharides from Inonotus obliquus.

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Citation abstract

This study was aimed to investigate the impacts of gastrointestinal digestion in vitro on the physicochemical properties and the biological activities of polysaccharides from Inonotus obliquus (UIOPS-1). Results showed that the monosaccharides composition, structure and conformation of polysaccharides were remarkably altered, and the molecular weight (Mw) of UIOPS-1 was steadily decreased from 105.02kDa to 88.97kDa and 36.74kDa after simulated digestion. The reducing ends were increased and the free monosaccharides including d-glucose, d-galactose and d-xylose were released suggested that the degradation of UIOPS-1 was caused by disrupting the aggregates and glycosidic bonds. The antioxidant activities of UIOPS-1 were significantly increased after gastric digestion (P<0.05), however, they were decreased after intestinal digestion. The α-amylase and α-glucosidase inhibitory activities of UIOPS-1 were significantly increased after digestion indicating a good control of postprandial hyperglycemia (P<0.001). The results indicated that UIOPS-1 still exhibited antioxidant and antihyperglycemic potential after gastrointestinal digestion, which could be considered as a promising candidate for functional foods.