Effect of in vitro simulated digestion on the biological activities of purified phenolic compounds from Moringa oleifera leaves

The biological activities of Moringa oleifera leaf polyphenols were tested after in vitro gastrointestinal (GI) digestion and colonic fermentation (CF). Following in vitro GI digestion and CF, total phenolic compounds (TPC) were reduced by 30% and 38.82%, respectively. Moringa polyphenol extract (MPPE) substantially reduced pancreatic lipase and alpha-glucosidase inhibition by 5.63% and 14.20% after GI digestion and 27.41% and 34.01% after CF. In contrast, inhibitory activity against alpha-amylase was eliminated with GI digestion and CF. Slight decreases in both antioxidant activity assays (DPPH and ABTS) after GI digestion and CF were observed. Cytotoxic activity against HeLa and HepG2 cancer cells was decreased after GI digestion and CF while anti-proliferation activity against HepG2 cells was improved after CF. MPPE significantly affected the abundance of gut microbiota groups, accordingly, could improve glucose metabolism, decline the energy harvest and subsequently reduce the risk of obesity.