Food Chemistry and Toxicology, University of Kaiserslautern, 67663, Kaiserslautern, Germany.
Food Chemistry and Toxicology, University of Kaiserslautern, 67663, Kaiserslautern, Germany.
Food Chem Toxicol. 2021 Feb;148:111923. doi: 10.1016/j.fct.2020.111923. Epub 2020 Dec 13.
In spite of its considerable value as a predictor of in vivo genotoxicity and even for carcinogenicity, false positive cases were reported for the Ames test, e.g., with a number of natural food constituents. Here we analyzed the effects of juice of Allium cepa, the common onion, a staple food and traditional remedy used in many civilizations, in the Ames fluctuation assay. We could find mild mutagenicity with an onion juice extract in Salmonella typhimurium strains TA98 and TA100, the latter being less sensitive towards the extract. Mutagenicity was not influenced markedly by the presence of rat liver S9 mix. Onion juice also exerted some toxicity to the bacteria in the same concentration range. Comparative studies with quercetin and rutin, major flavonoid glycosides in onions, revealed a mutagenic potency of quercetin with an EC-value of 4 μM in TA98. The contents of quercetin and rutin in onion juice were determined as 0.71 ± 0.20, and 0.71 ± 0.21 mg/kg. Calculations of quercetin and rutin concentrations in mutagenic dilutions revealed that both compounds are highly unlikely to cause the mutagenic effects of onion juice and that other yet undefined constituents must be responsible for these effects.
尽管其作为体内遗传毒性甚至致癌性的预测因子具有相当大的价值，但 Ames 试验还是报告了一些假阳性的情况，例如一些天然食物成分。在此，我们分析了洋葱汁（Allium cepa）的效果，洋葱是一种常用的食物和传统药物，在许多文明中都有使用。我们发现洋葱汁在鼠伤寒沙门氏菌 TA98 和 TA100 菌株中具有轻度致突变性，后者对提取物的敏感性较低。致突变性不受大鼠肝 S9 混合物的存在显著影响。洋葱汁在相同浓度范围内对细菌也有一定的毒性。与洋葱中的主要类黄酮糖苷槲皮素和芦丁的比较研究表明，在 TA98 中，槲皮素的致突变效力为 4 μM，EC 值。洋葱汁中槲皮素和芦丁的含量分别为 0.71 ± 0.20 和 0.71 ± 0.21 mg/kg。在致突变稀释液中计算槲皮素和芦丁的浓度表明，这两种化合物都不太可能引起洋葱汁的致突变作用，而其他尚未确定的成分必须对此负责。
