栄研スタッフによる解説論文集 資料　作成日　98/02/10
	Suppression of lipid photoperoxidation by quercetin and its glycosides in spinach chloroplasts
	著者: Takahama, U.
	出典: Photobiochem. Photobiol, 38, 363-367(1983)

要約

Quercetin, quercitrin and rutin suppressed lipid photoperoxidation in spinach chloroplasts in the presence of 100 ｵM carbonylcyanide m-chlorophenylhydrazone (CCCP) or 100 ｵM methyl viologen (MV). Fifty percent inhibition of lipid peroxidation by quercetin was observed between 30 and 50 ｵM. Concentrations of quercetin and rutin higher than 100 ｵM were required to obtain 50% inhibition. Quercitrin was more effective than rutin in the suppression of lipid photoperoxidation.

Photooxidation of the flavonols by chloroplasts in the presence of MV was suppressed by superoxide dismutase (SOD) more than 90%, and the rates of the oxidation decreased in order of quercetin, quercitrin and rutin suggesting that the reactivity of the flavonols with 02- decreased in that order. The photooxidation of the flavonols by CCCP-poisoned chloroplasts was partially suppressed by SOD. Radicals generated in the course of lauroyl peroxide degradation also oxidized the flavonols and the oxidation was insensitive to SOD. In these experiments, oxidation rate of quercetin was faster than those of its glycosides. The results obtained suggest that flavonols can function as antioxidants in chloroplasts by scavenging both 02- and the radicals formed during lipid peroxidation.

(c) All Copyrights reserved 2001 National Institute of Health and Nutrition