Phenolic antioxidants isolated from the flowers of Osmanthus fragrans

Abstract

O. fragrans has slightly less antioxidative activity than green tea. Five phenolic compounds, tyrosyl acetate (1), (+)-phillygenin (2), (8E)-ligustroside (3), rutin (4), and verbascoside (5), were isolated from the CHCl3 sub-extract of O. fragrans. The structures were elucidated by interpreting their spectral data. Evaluation of the antioxidative property of the isolated (+)-phillygenin (2), rutin (4), and verbascoside (5) revealed strong DPPH radical scavenging activity, with IC 50 values of 19.1, 10.3, and 6.2 μM, respectively. These isolates also exhibited an H 2O 2 scavenging ability, with IC 50 values of 10.5, 23.4, and 13.4 μM, respectively. © 2012 by the authors.