The phytochemical composition, metabolites, bioavailability and in vivo antioxidant activity of Tetrastigma hemsleyanum leaves in rats

Tetrastigma hemsleyanum is a traditional edible and medicinal plant in China. The phytochemical composition of its leaf (THL) and the bioavailability and metabolism of these compounds and their metabolites in vivo are less known. A metabolomics approach was therefore taken by using UPLC-ESI-QTOF-MS2. A total of 75 compounds were tentatively characterized in THL. Ten original compounds and 11 metabolites observed in plasma, and 20 original compounds and 26 metabolites detected in urine. Meanwhile, rats treated with THL extract in an oxidative stress model showed significantly increased total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities and glutathione (GSH) content and decreased malondialdehyde (MDA) content in plasma and tissues. Results suggest THL phenolics are bioavailable, and these compounds and their metabolites are likely behind the observed activities. The present study demonstrates that THL extract as a good source of antioxidant ingredient for the safeguard against oxidative stress-related chronic diseases.