Antioxidant Benzoylated Flavan-3-ol Glycoside from Celastrus orbiculatus

Abstract
A new flavan-3-ol glycoside, (−)-epicatechin-5-O-β-d-glucosyl-3-benzoate (1), and two known compounds, (−)-epicatechin and (−)-epiafzelechin, were isolated from an EtOAc extract of Celastrus orbiculatus aerial parts that exhibited significant antioxidant effect in a 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical assay. The structure of 1 was elucidated by spectroscopic analyses, and compound 1 and its aglycon, (−)-epicatechin-3-benzoate (2), were found to be moderately active as antioxidants in the DPPH assay.