Screening strategy for predominant phenolic components of digestive enzyme inhibitors in passion fruit peel extracts on simulated gastrointestinal digestion.

BACKGROUND: The targeted biological activity of a natural product is often the result of the combined action of multiple functional components. Screening for predominant contributing components of targeting activity is crucial for quality evaluation. RESULTS: Thirteen and nine phenolic compounds inhibiting α-glucosidase and α-amylase, respectively, were identified in the ethanol extracts of passion fruit peel through liquid chromatography-tandem mass spectrometry and multivariate analysis. Considering the different concentrations of components and their interactions, the role of the semi-inhibitory concentration (IC50 ) in the dose-effect relationship is limited. We proposed the active contribution rate (ACR), which is the ratio of a single component concentration to its IC50 in the whole, to assess the relative activity of each compound. Luteolin, quercetin, and vitexin exhibited a minimum IC50 . Before the simulation of gastrointestinal digestion, quercetin, salicylic acid, and luteolin were identified as the dominant contributors to α-glucosidase inhibition according to ACR, while salicylic acid, 2,3-dihydroxybenzoic acid, and quercetin were identified as dominant contributors to α-amylase inhibition. After simulated digestion, the contents of all polyphenolic compounds decreased by various degrees. Salicylic acid, gentisic acid, and vitexin became the dominant inhibitors of α-glucosidase based on ACR (cumulative 57.96%), while salicylic acid and 2,3-dihydroxybenzoic acid became the dominant inhibitors of α-amylase (cumulative 84.50%). CONCLUSION: Therefore, the ACR evaluation strategy can provide a quantitative reference for screening the predominant contributor components of a specific activity in complex systems. © 2022 Society of Chemical Industry.

Phenolic compounds, bioactivity, and bioaccessibility of ethanol extracts from passion fruit peel based on simulated gastrointestinal digestion.

Passion fruit peel, a potential source of bioactive compounds, has been used as food stabilizing agent. However, the phenolic composition and bioactivity of passion fruit peel have rarely been reported. The effects of simulated gastrointestinal digestion on the bioactive components, bioactivity and bioaccessibility of passion fruit peel ethanol extracts (PFPE) were investigated using high performance liquid chromatography-tandem mass spectrometry analysis (quasi-targeted metabolomics). Phenols (178) were identified, of which 25 inhibited alpha-glucosidase activity. The stabilities of PFPE phenols were significantly affected by pH changes and digestive enzymes during simulated digestion. The 1,1-diphenyl-2-picrylhydrazyl free radical scavenging capacity and ferric ion reducing antioxidant power were decreased by 32% and 30%, respectively, while 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) free radical scavenging capacity increased by 17%. Alpha-glucosidase inhibition decreased with decreased PFPE phenolic content. Therefore, passion fruit peel could be considered a source of natural antioxidants and alpha-glucosidase inhibitors.