Antioxidant benzoylated flavan-3-ol glycoside from Celastrus orbiculatus.

A new flavan-3-ol glycoside, (-)-epicatechin-5-O-beta-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.