Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/no, Ribeirão Preto, São Paulo, CEP 14040-903, Brazil.
Arch Toxicol. 2011 Sep;85(9):1151-7. doi: 10.1007/s00204-011-0652-y. Epub 2011 Feb 1.
Aim of the study was to find out whether consumption of quercetin (QC), an abundant flavonoid in the human diet, protects against DNA damage caused by exposure to organic mercury. Therefore, rats were treated orally with methylmercury (MeHg) and the flavonoid with doses that reflect the human exposure. The animals received MeHg (30 μg/kg/bw/day), QC (0.5-50 mg/kg/bw/day), or combinations of both over 45 days. Subsequently, the glutathione levels (GSH) and the activities of glutathione peroxidase (GPx) and catalase (CAT) were determined, and DNA damage was measured in hepatocytes and peripheral leukocytes in single cell gel electrophoresis assays. MeHg decreased the concentration of GSH and the activity of GPx by 17 and 12%, respectively and caused DNA damage to liver and blood cells, while with QC no such effects were seen. When the flavonoid was given in combination with MeHg, the intermediate and the highest concentrations (5.0 and 50.0 mg/kg/bw/day) were found to cause DNA protection; DNA migration was reduced by 54 and 65% in the hepatocytes and by 27 and 36% in the leukocytes; furthermore, the reduction in GSH and GPx levels caused by MeHg treatment was restored. In summary, our results indicate that consumption of QC-rich foods may protect Hg-exposed humans against the adverse health effects of the metal.
本研究旨在探讨膳食中丰富的类黄酮槲皮素（QC）的摄入是否能预防有机汞暴露引起的 DNA 损伤。因此，实验用甲基汞（MeHg）和类黄酮对大鼠进行了口服处理，剂量反映了人类的暴露量。这些动物在 45 天内分别接受了 MeHg（30μg/kg/bw/天）、QC（0.5-50mg/kg/bw/天）或两者的组合。随后，测定了谷胱甘肽水平（GSH）、谷胱甘肽过氧化物酶（GPx）和过氧化氢酶（CAT）的活性，并在单细胞凝胶电泳试验中测定了肝细胞和外周血白细胞中的 DNA 损伤。MeHg 使 GSH 浓度降低 17%，GPx 活性降低 12%，导致肝和血细胞的 DNA 损伤，而 QC 则没有这些作用。当类黄酮与 MeHg 一起使用时，中浓度（5.0mg/kg/bw/天）和高浓度（50.0mg/kg/bw/天）被发现具有 DNA 保护作用；在肝细胞中，DNA 迁移减少了 54%和 65%；在白细胞中，DNA 迁移减少了 27%和 36%；此外，MeHg 处理导致的 GSH 和 GPx 水平降低得到了恢复。综上所述，我们的结果表明，富含 QC 的食物的摄入可能会使接触汞的人群免受该金属的不良健康影响。
