Rapid characterization of chemical constituents in Radix Tetrastigma, a functional herbal mixture, before and after metabolism and their antioxidant/antiproliferative activities

Radix Tetrastigma (RT), the roots of Tetrastigma hemsleyanum Diels et Gilg, is consumed as both functional food and traditional medicinal herb in China, but there is rare report on its bioactive components. In the present study, the total flavonoid contents (TFC) and antioxidant/antiproliferative activities of RT were evaluated, and the chemical constituents of RT and their metabolites of rat after oral administration were identified and quantified by UPLC-ESI-QTOF-MS/MS and UPLC-ESI-QqQ-MS/MS. The extract of RT exhibited high TFC and antioxidant/antiproliferative activities in which there were 58 compounds characterized or tentatively identified. Nine original compounds and 12 metabolites were detected in plasma, while 11 original compounds and 13 metabolites were observed in urine. Nine flavonoids were quantified and 5 of them (catechin, kaempferol-3-rutinoside, rutin, isoquercitrin and astragalin) were up to 71.46% of TFC; their metabolites were also found in the plasma and urine, which was suggested to be the major antioxidant/antiproliferative compounds.