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 alpha-glucosidase and alpha-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 alpha-glucosidase inhibition according to ACR, while salicylic acid, 2,3-dihydroxybenzoic acid, and quercetin were identified as dominant contributors to alpha-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 alpha-glucosidase based on ACR (cumulative 57.96%), while salicylic acid and 2,3-dihydroxybenzoic acid became the dominant inhibitors of alpha-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. (C) 2022 Society of Chemical Industry.

Automated summary

This study identified multiple phenolic compounds in passion fruit peel using liquid chromatography-tandem mass spectrometry and multivariate analysis. The relative activity of these compounds in inhibiting alpha-glucosidase and alpha-amylase was evaluated using the active contribution rate (ACR). The results showed that the inhibitory capacity of the compounds changed after simulated digestion.