Effects of Eucommia ulmoides Oliver leaves on gut microbiota and intestinal function during in vitro simulated digestion and fermentation

In this study, the effects of Eucommia ulmoides Oliver (EUO) leaves, both young and mature, on intestinal health were evaluated using in vitro simulated digestion and fermentation model. During the digestion phase, we observed that digestive enzymes gradually released polyphenols from the EUO leaves. Notably, the digestion products of EUO young leaves (EUO-YL) had higher polyphenol content and antioxidant activity compared to those of EUO mature leaves (EUO-ML). In the fermentation stage, the digestion products of EUO leaves effectively modulated the gut microbiota by increasing the relative abundances of short-chain fatty acids (SCFAs) producing bacteria, leading to higher SCFAs concentrations in the EUO leaf supplement groups. Additionally, the fermentation products of EUO leaves improved intestinal barrier function and decreased pro-inflammatory cytokine levels in Caco-2/THP1 co-cultures exposed to lipopolysaccharide (LPS). Our research supports the potential of EUO leaves as a functional food source for the prevention or treatment of related diseases.