Biological and Pharmaceutical Bulletin
Online ISSN : 1347-5215
Print ISSN : 0918-6158
ISSN-L : 0918-6158
Inhibitory Effect of Oolong Tea on the Oxidative State of Low Density Lipoprotein (LDL)
Hiroshi KuriharaHarukazu FukamiYoshiko ToyodaNorihiko KageyamaNobuo TsuruokaHiroshi ShibataYoshinobu KisoTakaharu Tanaka
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2003 Volume 26 Issue 5 Pages 739-742


In the present study, we investigated the anti-oxidant activity of oolong tea in an oxidation model using human low-density lipoprotein (LDL). Oolong tea suppressed the oxidation of LDL induced by 2-2′-azobis 4-methoxy-2,4-dimethyvaleronitrile (V70) in a dose-dependent manner, that is, it prolonged the lag time to 114.3%, 138% and 199.9% as compared with the control group at 0.5 μg/ml, 1.0 μg/ml, and 2.5 μg/ml, respectively. We also determined the scavenging effect of oolong tea on active oxygen radicals using the electron spin resonance (ESR) technique with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trapping agent. The intensity of the ESR signals for the DMPO–OOH adduct formed by the hypoxanthine/xanthine oxidase reaction system with DMPO decreased in the presence of oolong tea. The IC50 of oolong tea was 19.9 μg/ml. These findings suggested that oolong tea has beneficial effects on health related to its anti-oxidative action.

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© 2003 The Pharmaceutical Society of Japan
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