Identification of antioxidant compounds of Mucuna sempervirens by high-speed counter-current chromatographic separation–DPPH radical scavenging detection and their oestrogenic activity

High-speed counter-current chromatography (HSCCC) was used to separate an ethanolic extract of leaves of Mucuna sempervirens into fractions which were then detected their antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The fractions were grouped into seven larger fractions (components) based on their antioxidant activity. The seven components were isolated by preparative HPLC to yield 12 flavonoids and two phenolic acids identified by electrospray ionisation mass spectrometry and nuclear magnetic resonance analyses. The oestrogenic activity of the 12 isolated flavonoids was evaluated by the luciferase assay based on the MVLN cell line. The results indicate that leaves of M. sempervirens are a flavonoid-rich resource that may supply antioxidant and oestrogenic compounds to the human body. The HSCCC separation–DPPH radical scavenging detection could be widely applied for rapid screening and isolation of antioxidants from complex plant extracts.