Pardo-Andreu Gilberto Lázaro, Delgado René, Núñez-Sellés Alberto J, Vercesi Anibal E
Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-970 Campinas, SP, Brasil.
Phytother Res. 2006 Feb;20(2):120-4. doi: 10.1002/ptr.1813.
Vimang is an aqueous extract of selected species of Mangifera indica L, used in Cuba as a nutritional antioxidant supplement. Many in vitro and in vivo models of oxidative stress have been used to elucidate the antioxidant mechanisms of this extract. To further characterize the mechanism of Vimang action, its effect on the degradation of 2-deoxyribose induced by Fe (III)-EDTA plus ascorbate or plus hypoxanthine/xanthine oxidase was studied. Vimang was shown to be a potent inhibitor of 2-deoxyribose degradation mediated by Fe (III)-EDTA plus ascorbate or superoxide (O2-). The results revealed that Vimang, at concentrations higher than 50 microM mangiferin equivalent, was equally effective in preventing degradation of both 15 mM and 1.5 mM 2-deoxyribose. At a fixed Fe (III) concentration, increasing the concentration of ligands (either EDTA or citrate) caused a significant reduction in the protective effects of Vimang. When ascorbate was replaced by O2- (formed by hypoxanthine and xanthine oxidase) the protective efficiency of Vimang was also inversely related to EDTA concentration. The results strongly indicate that Vimang does not block 2-deoxyribose degradation by simply trapping *OH radicals. Rather, Vimang seems to act as an antioxidant by complexing iron ions, rendering them inactive or poorly active in the Fenton reaction.
维芒是从芒果(Mangifera indica L.)特定品种中提取的水提取物,在古巴用作营养抗氧化剂补充剂。许多氧化应激的体外和体内模型已被用于阐明这种提取物的抗氧化机制。为了进一步表征维芒的作用机制,研究了其对由Fe(III)-EDTA加抗坏血酸或加次黄嘌呤/黄嘌呤氧化酶诱导的2-脱氧核糖降解的影响。结果表明,维芒是由Fe(III)-EDTA加抗坏血酸或超氧化物(O2-)介导的2-脱氧核糖降解的有效抑制剂。结果显示,当浓度高于50μM芒果苷当量时,维芒在防止15 mM和1.5 mM 2-脱氧核糖降解方面同样有效。在固定的Fe(III)浓度下,增加配体(EDTA或柠檬酸盐)的浓度会导致维芒的保护作用显著降低。当抗坏血酸被O2-(由次黄嘌呤和黄嘌呤氧化酶形成)取代时,维芒的保护效率也与EDTA浓度呈负相关。结果有力地表明,维芒不是通过简单地捕获*OH自由基来阻止2-脱氧核糖降解。相反,维芒似乎通过络合铁离子发挥抗氧化作用,使它们在芬顿反应中失活或活性降低。