Inhibitory effect of oolong tea on the oxidative state of low density lipoprotein (LDL).
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 microg/ml, 1.0 microg/ml, and 2.5 microg/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 IC(50) of oolong tea was 19.9 microg/ml. These findings suggested that oolong tea has beneficial effects on health related to its anti-oxidative action.
Kurihara
Hiroshi
H
Institute for Health Care Science, Suntory Ltd., Wakayamadai, Shimamoto-cho, Mishima-gun, Osaka, Japan. Hiroshi_Kurihara@suntory.co.jp
Fukami
Harukazu
H
Toyoda
Yoshiko
Y
Kageyama
Norihiko
N
Tsuruoka
Nobuo
N
Shibata
Hiroshi
H
Kiso
Yoshinobu
Y
Tanaka
Takaharu
T
D000975:Antioxidants / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry; D006801:Humans; D008077:Lipoproteins, LDL / Q000737:chemistry*; D008297:Male; D010084:Oxidation-Reduction; D010936:Plant Extracts / Q000737:chemistry; D013481:Superoxides / Q000737:chemistry; D013662:Tea / Q000737:chemistry*
D000975:Antioxidants; D016166:Free Radical Scavengers; D008077:Lipoproteins, LDL; D010936:Plant Extracts; D013662:Tea; D013481:Superoxides