Boadi William Y, Iyere Peter A, Adunyah Samuel E
Department of Chemistry, Tennessee State University, 3500 John A. Merritt Boulevard, Nashville, TN 37209, USA.
J Appl Toxicol. 2003 Sep-Oct;23(5):363-9. doi: 10.1002/jat.933.
The single and combined effects of two abundant flavonoids, namely quercetin and genistein, were investigated according to their ability to inhibit the oxidation of methyl linolenate via Fenton's pathway. Antioxidative activity was determined by oxidizing methyl linolenate suspended in a buffer solution with either Fe2+ (50 microM) or Cu2+ (50 microM) and hydrogen peroxide (0.01 mM) without or with a flavonoid sample (10 or 20 microM). Lipid peroxidation products were measured by the thiobarbituric acid (TBA) assay and the amounts of thiobarbituric acid-reactive substances (TBARS) were calculated from a calibration curve using 1,1,3,3-tetraethoxypropane as the standard. Both quercetin and genistein at the 10 or 20 microM level decreased lipid peroxidation significantly compared with their respective controls. Of the two flavonoids tested, quercetin had a more marked effect on inhibiting lipid peroxides. Peroxidation products for the control samples were higher for the Fe2+-treated samples compared with the Cu2+ samples. Combination of both flavonoids at the same dose levels continued to decrease lipid peroxidation, the effect being the same for both metal ions. The data suggest that the combined flavonoids offered better protection than the single treatments and this may be attributed to the better radical scavenging or increased chelating capabilities of the combined over the single treatments. The differences in peroxide levels for the single treatment of quercetin compared with the genistein-treated samples may reflect the structural differences between these compounds in combating oxidative stress.
根据槲皮素和染料木黄酮这两种丰富的类黄酮通过芬顿途径抑制亚麻酸甲酯氧化的能力，研究了它们的单一作用和联合作用。抗氧化活性的测定方法是：在有无类黄酮样品（10或20微摩尔）的情况下，用Fe2+（50微摩尔）或Cu2+（50微摩尔）和过氧化氢（0.01毫摩尔）氧化悬浮在缓冲溶液中的亚麻酸甲酯。通过硫代巴比妥酸（TBA）测定法测量脂质过氧化产物，并以1,1,3,3 - 四乙氧基丙烷为标准，根据校准曲线计算硫代巴比妥酸反应性物质（TBARS）的量。与各自的对照相比，10或20微摩尔水平的槲皮素和染料木黄酮均显著降低了脂质过氧化。在测试的两种类黄酮中，槲皮素对抑制脂质过氧化物的作用更为显著。与Cu2+处理的样品相比，Fe2+处理的样品的对照样品的过氧化产物更高。相同剂量水平的两种类黄酮联合使用继续降低脂质过氧化，对两种金属离子的作用相同。数据表明，联合使用类黄酮比单一处理提供了更好的保护，这可能归因于联合处理比单一处理具有更好的自由基清除能力或增强的螯合能力。与染料木黄酮处理的样品相比，槲皮素单一处理的过氧化物水平差异可能反映了这些化合物在对抗氧化应激方面的结构差异。
