Phytochemical bioaccessibility and <i>in vitro</i> antidiabetic effects of Chinese sumac ( <i>Rhus chinensis</i> Mill.) fruits after a simulated digestion: insights into the mechanisms with molecular docking analysis

Abstract

Abstract This work studied the effects of gastrointestinal digestion on the phytochemical bioaccessibility and in vitro anti‐diabetic effects of different fractions from Chinese sumac fruits and delineated the underlying mechanisms by molecular docking. Results showed that gastric digestion significantly increased the phytochemical bioaccessibility and inhibitions for α‐glucosidase, dipeptidyl peptidase‐4 (DPP‐IV) and advanced glycation end product (AGE) formation of the ethanol‐extracted fraction, whereas intestinal digestion remarkably decreased these parameters ( P &lt; 0.05). For the free phenolic fraction, the parameters were remarkably reduced after gastric digestion but significantly increased after intestinal digestion ( P &lt; 0.05). Quercitrin and gvajaverin contributed the most to the α‐glucosidase and DPP‐IV inhibitions, and trigalloyl glucose and its isomer could be the primary bioactive substance responsible for AGE suppression. Quercitrin, the predominant phenolic compound, could effectively interact with crucial amino acid residues in α‐glucosidase, DPP‐IV and bovine serum albumin with hydrogen bonds and hydrophobic interactions to exert its inhibitions.