Vuković-Gacić B, Simić D
Botanical Institute and Garden, University of Belgrade, Yugoslavia.
Basic Life Sci. 1993;61:269-77. doi: 10.1007/978-1-4615-2984-2_25.
The results of a study of bioantimutagenesis, with emphasis on natural antimutagens from plant extracts with modulating effects on DNA repair in Escherichia coli bacteria are presented in this chapter. Comparative screening for spontaneous or induced mutagenesis, as well as expression of the SOS gene, sfiA was accomplished. Antimutagenic capacity was obtained with nontoxic concentrations of the plant extracts; the same plant extract may decrease or increase the mutation rate, or even be ineffective, depending on the bacterial strain used and the concentration of the extract applied. Since antimutagenic effects may be the consequence of either stimulation of error-free repair, inhibition of error-prone repair, or involvement of multiple mechanisms, the effects of several plant extracts on the level of UV-induced beta-galactosidase were screened (to monitor SOS induction in cells). Reduction of the enzyme activity induced by UV was observed following addition of St. John's wort extract, while there was not reduction after thyme, aloe, camomile, or lime-tree and the level of UV-induced enzyme was even higher with sage extract. Our results indicate that the antimutagenic effect of St. John's wort is probably due to suppression of error-prone repair. Moreover, we assume that an antimutagenic effect obtained with thyme, mint, and sage under certain conditions may be due to enhanced error-free repair.
本章介绍了一项生物抗诱变研究的结果，重点是来自植物提取物的天然抗诱变剂对大肠杆菌DNA修复的调节作用。完成了对自发或诱导诱变以及SOS基因sfiA表达的比较筛选。通过无毒浓度的植物提取物获得抗诱变能力；根据所用细菌菌株和提取物浓度的不同，相同的植物提取物可能会降低或提高突变率，甚至无效。由于抗诱变作用可能是刺激无差错修复、抑制易错修复或多种机制共同作用的结果，因此筛选了几种植物提取物对紫外线诱导的β-半乳糖苷酶水平的影响（以监测细胞中的SOS诱导）。添加圣约翰草提取物后，观察到紫外线诱导的酶活性降低，而百里香、芦荟、洋甘菊或菩提树提取物添加后酶活性没有降低，鼠尾草提取物处理后紫外线诱导的酶水平甚至更高。我们的结果表明，圣约翰草的抗诱变作用可能是由于抑制了易错修复。此外，我们推测在某些条件下，百里香、薄荷和鼠尾草获得的抗诱变作用可能是由于增强了无差错修复。
