Herba Epimedii biotransformation in in vitro simulated gastrointestinal digestion and faecal fermentation systems

Abstract

Epimedium has been widely used in ethnopharmacological practices, and is rich in a variety of beneficial active ingredients, however, its biotransformation in simulated gastrointestinal digestion remains unclear. The dynamic changes of components of Epimedium during the simulated gastrointestinal digestion and subsequent human faecal fermentation were investigated by UPLC-MS, HPLC-DAD and multivariate data analysis. Epimedium samples were subjected to HPLC-fingerprints and 60 peaks (compounds) of digestive products of different stages were collected to analyze the effects of Epimedium’s gastrointestinal metabolisms. The major bioactive flavonoids ingredients, epimedin C, icariin and baohuoside I, were identified among the compounds. Application of PCA to HPLC data showed that there were obvious differences among the samples after gastric, saliva, intestinal digestion, colonic fermentation at 0.5 h and other times (24 h, 48 h and 72 h). The contents of epimedin C, icariin and baohuoside I all decreased significantly after gastric digestion, while increased significantly after intestinal digestion. UPLC-MS analysis indicated difference between the samples after gastric digestion and saliva digestion in component, possibly due to a series of gastric environmental factors such as low pH and pepsin etc. Additionally, after colonic fermentation simulation stage, the components of Epimedium changed obviously, this may be due to the fact that most of the glycosylated flavonoids of Epimedium were decomposed into phenolic acids. This study provides scientific basis for rational assessment and application of Epimedium.