期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：2001
卷号：47
期号：4
页码：306-310
DOI：10.3177/jnsv.47.306
出版社：Center for Academic Publications Japan
摘要：Vitamin B6 deficiency increases the lipid peroxidation and the synthesis of xanthurenic acid from tryptophan. Antioxidant properties of xanthurenic acid were exam-ined in relation to the coordination of transition metals. Xanthurenic acid inhibited the for-mation of thiobarbituric acid-reactive substances as a marker of iron-mediated lipid peroxi-dation and copper-dependent oxidation of low density lipoprotein. NADP-isocitrate dehydro-genase (EC 1.1.1.42), a principal NADPH-generating enzyme for the antioxidant defense system, was inactivated by reduced iron and copper, and xanthurenic acid protected the en-zyme from the Fe2+-mediated inactivation. Xanthurenic acid may participate in the en-hanced regeneration of reduced glutathione by stimulating the NADPH supply. Xanthurenic acid further enhanced the autooxidation of Fe2+ ion. Other tryptophan metabolites such as kynurenic acid and various quinoline compounds did not inhibit the lipid peroxidation and the inactivation of NADP-isocitrate dehydrogenase, and they showed little or no effect on the Fe2+ autooxidation. The antioxidant properties of xanthurenic acid are related to the metal-chelating activity and probably to the enhanced oxidation of reduced transition met-als as a prooxidant, and this action may be due to the electron deficient nature of this com-pound.
关键词：xanthurenic acid;antioxidant;LDL;NADP-isocitrate dehydrogenase;reactive oxygen species
