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Identification of natural antimutagens with modulating effects on DNA repair
1Botanical Institute and Garden, University of Belgrade, Yugoslavia.
Abstract:
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.
Insights
Natural plant extracts show potential for bioantimutagenesis by modulating DNA repair in bacteria. Some extracts, like St. John
Area of Science:
- * Molecular Biology
- * Genetics
- * Pharmacognosy
Background:
- * Bioantimutagenesis involves natural compounds that reduce mutagenicity.
- * Plant extracts contain diverse phytochemicals with potential biological activities.
- * DNA repair mechanisms in bacteria are crucial for genomic stability.
Purpose of the Study:
- * To investigate the bioantimutagenic effects of various plant extracts on DNA repair in Escherichia coli.
- * To screen for plant-derived antimutagens capable of modulating spontaneous and induced mutagenesis.
- * To elucidate the mechanisms underlying the observed antimutagenic effects, focusing on DNA repair pathways.
Main Methods:
- * Comparative screening of plant extracts for effects on spontaneous and induced mutagenesis in E. coli.
- * Assessment of the SOS gene (sfiA) expression to evaluate DNA damage response.
- * Measurement of UV-induced beta-galactosidase activity to monitor SOS induction and repair pathway modulation.
Main Results:
- * Nontoxic concentrations of certain plant extracts exhibited antimutagenic capacity.
- * St. John's wort extract reduced UV-induced enzyme activity, suggesting suppression of error-prone repair.
- * Thyme, mint, and sage extracts, under specific conditions, may enhance error-free repair, while others showed varied effects.
Conclusions:
- * Plant extracts can act as natural antimutagens by influencing bacterial DNA repair mechanisms.
- * St. John's wort demonstrates potential for suppressing error-prone DNA repair pathways.
- * The specific effects of plant extracts on mutagenesis depend on bacterial strain and extract concentration, highlighting the complexity of bioantimutagenesis.