Edenharder R, Pfeiffer E H
Hygiene-Institut, Universität Mainz.
Zentralbl Hyg Umweltmed. 1992 Jun;193(1):53-66.
Low levels of mutagenic activities were detected in only 5-25% of the feces of people on a normal mixed-western diet, when feces were extracted by solvents and extracts were analyzed for mutagenicity with Ames' standard Salmonella/microsome assay. Since mutagens are know to be present in this type of diet and may be synthesized endogenously by bacteria in the large bowel, the question is if antimutagenic compounds mask the presence of genotoxic substances. We therefore tested the inhibition of known mutagens--benzo(a)-pyrene and sodium azide--by acetone/ethyl-acetate extracts of lyophilized feces in model experiments. These extracts completely suppressed the mutagenicity of benzo(a)pyrene and reduced the mutagenicity of sodium azide by about 60%, but were non-cytotoxic. Using gel filtration over Sephadex LH-20 and subsequent silica gel column chromatography we found that the inhibitors were polar organic compounds with molecular weights about 500 or more. The inhibitory effect could not be changed by esterification or saponification methods but was completely abolished by alkaline potassium permanganate oxidation. We therefore conclude that the antimutagenic activities might be identical with bile pigments.
当用溶剂提取正常西方混合饮食人群的粪便，并采用艾姆斯标准沙门氏菌/微粒体试验分析提取物的致突变性时，仅在5%-25%的粪便中检测到低水平的诱变活性。由于已知这种饮食类型中存在诱变剂，并且可能由大肠中的细菌内源性合成，问题在于抗诱变化合物是否掩盖了遗传毒性物质的存在。因此，我们在模型实验中测试了冻干粪便的丙酮/乙酸乙酯提取物对已知诱变剂——苯并(a)芘和叠氮化钠的抑制作用。这些提取物完全抑制了苯并(a)芘的诱变性，并使叠氮化钠的诱变性降低了约60%，但无细胞毒性。通过葡聚糖凝胶LH-20凝胶过滤和随后的硅胶柱色谱法，我们发现抑制剂是分子量约为500或更大的极性有机化合物。酯化或皂化方法不能改变抑制作用，但碱性高锰酸钾氧化可使其完全消除。因此，我们得出结论，抗诱变活性可能与胆色素相同。
