Separation and purification of antioxidant peptides from Idesia polycarpa Maxim. cake meal and study of conformational relationship between them

Abstract

AbstractIn this study, peptides were isolated and purified from Idesia polycarpa Maxim. cake meal for the first time, with the aim of discovering peptides with excellent antioxidant properties. Peptides were isolated and purified from the cake meal using ultrafiltration and dextran gel chromatography. Fractions with significant antioxidant activity were identified by mass spectrometry (MS) and the peptides were screened and characterized using techniques, such as network pharmacology and molecular docking. The results showed that the CIPs‐I‐F2 fractions possessed excellent antioxidant activities, and a total of seven peptides were screened, with the main targets of action including serine/threonine‐protein kinase AKT (AKT1), signal transducer and activator of transcription 3 (STAT3), and matrix metalloproteinase 9 (MMP9), among which ISKPTWADF had the highest total binding energy to the target. ISKPTWADF was synthesized in vitro by solid‐phase synthesis and showed a dose‐dependent protective effect against the hydrogen peroxide (H2O2)‐induced oxidative damage model in human hepatocellular carcinoma HepG2 cells, with its main active site on the tryptophan indole ring at position 52N‐127H.