Radical Scavenging Activity of Phenylpropanoid Glycosides in<i>Caryopteris incana</i>

Abstract

In our screening program for antioxidants from traditional drugs and foodstuffs, one new phenylpropanoid glycoside, incanoside, was isolated together with four known phenylpropanoid glycosides, verbascoside, isoverbascoside, phlinoside A, and 6-O-caffeoyl-beta-D-glucose from the whole plant of Caryopteris incana (Thunb.) Miq. On the basis of chemical evidence and spectral analysis data, the structure of incanoside was determined to be 1-O-(3,4-dihydroxyphenyl)ethyl-O-beta-D-glucopyranosyl (1-->2)-alpha-L-rhamnopyranosyl(1-->3)-6-O-caffeoyl-beta-D- glucopyranoside. The four phenylpropanoid glycosides exhibited potent radical scavenging activity against DPPH, hydroxyl (.OH), and superoxide anion (O2-.) radicals.