• Natural Product Sciences
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• v.14 no.2
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• pp.107-112
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• 2008

The six phenolic compounds isolated from the root of Dipsacus asper, 3,4-di-O-caffeoylquinic acid (1), methyl 3,4-di-O-caffeoyl quinate (2), 3,5-di-O-caffeoylquinic acid (3), methyl 3,5-di-O-caffeoyl quinate (4), 4-5-di-O-caffeoylquinic acid (5), methyl 4,5-di-O-caffeoyl quinate (6) were continuously evaluated for their antioxidant activity using superoxide radical scavenging and AAPH-mediated (LDL) oxidation assay. The results demonstrated that compounds 1 - 6 had remarkable antioxidant activities with the $IC_50$ values ranging from 12.0 to $2.8{\mu}M$ in superoxide radical scavenging. They also inhibited AAPH-mediated low-density lipoprotein LDL oxidation by the generation of thiobarbituric acid reactive substances (TBARS) with $IC_50$ ranging from 6.7 to $8.7{\mu}M$.