Abstract: Passion fruit peel powder (PFP), ethanol extract (PFPE) and residue (PFPR) from passion fruit peel, and soluble (PFSF) and insoluble dietary fiber (PFIF) from passion fruit peel were evaluated for their in vitro inhibitory effect on glucose absorption, antioxidant activity and regulatory effect on intestinal microflora structure in hyperglycemic rats. The results showed that PFPE had an obvious scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radicals, and showed a strong inhibitory effect on α-glucosidase and α-amylase activities, with half-maximal inhibitory concentration (IC50) of 1.89, 32.25, 6.23 and 28.65 mg/mL, respectively. The composition analysis revealed that total phenols and flavonoids were the main components responsible for the antioxidant and enzyme inhibitory activities of PFPE. Passion fruit peel dietary fiber, especially PFSF, made a major contribution to delayed glucose absorption. All tested samples could be utilized by the intestinal microflora of hyperglycemic rats to produce short-chain fatty acids (SCFAs), and they could enrich Lactobacillus and Bifidobacterium to different degrees, and inhibit Enterococcus and Bacteroidetes, with PFSF being the most effective in regulating intestinal microflora structure in hyperglycemic rats.

Key words: passion fruit peel; antioxidant; intestinal microflora; glucose absorption; polyphenol; dietary fiber