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Summary A number of 1-methyl-1 H -imidazole derivatives and some of their oxygenated products were synthesized. An HPTLC technique for following the oxidation reactions in the different experimental conditions used was applied. The X-ray crystal structures of 1-methyl-2-methylsulfanyl-5-nitro-1 H -imidazole, 2-methanesulfinyl-1-methyl-5-nitro-1 H -imidazole and 2-methanesulfonyl-1-methyl-5-nitro-1 H -imidazole were determined. The compounds obtained were investigated for antimycotic and genotoxic activities. The compounds tested were found to exert very low growth inhibition against yeasts and moulds. Moderate antifungal properties against dermatophytes were demonstrated for 5-nitro derivatives. 2-Methanesulfonyl-1-methyl-5-nitro-1 H -imidazole was the most active substance. All 5-nitroimidazoles were genotoxic in Bacillus subtilis rec -assay, Salmonella microsome test and in Saccharomyces cerevisiae mitotic segregation assay. Structure-activity relationships are discussed.

The effects of Glycyrrhiza glabra L. extract, glycyrrhizinic acid, 18 alpha- and 18 beta-glycyrrhetinic acids on the mutagenicity of the ethyl methanesulfonate, N-methyl-N'-nitro-N-nitrosoguanidine, and ribose-lysine Maillard model systems were investigated by using the Salmonella/microsome reversion assay. The protocol used allowed us to detect desmutagenic and antimutagenic activity and to avoid false positive results due to toxicity. For all the compounds tested, no desmutagenic activity was observed against ethyl methanesulfonate and N-methyl-N'-nitro-N-nitrosoguanidine; only Glycyrrhiza glabra extract showed antimutagenic activity against ethyl methanesulfonate. On using the ribose-lysine mutagenic browning mixture, the desmutagenic activities of the Glycyrrhiza glabra extract, glycyrrhizinic acid, 18 alpha- and 18 beta-glycyrrhetinic acids were observed. 18 beta-Glycyrrhetinic acid was the most active compound. Glycyrrhiza glabra extract also exhibited antimutagenic activity against ribose-lysine.

Genotoxic properties of essential oils from Anthemis nobilis L., Artemisia dracunculus L., Salvia officinalis L., Salvia sclarea L., Satureja hortensis L., Satureja montana L., Thymus capitatus L., Thymus citriodorus Schreb., Thymus vulgaris L., Citrus bergamia Risso, were studied with Bacillus subtilis rec-assay and Salmonella/microsome reversion assay. The essential oil of Artemisia dracunculus L. "Piemontese" turned out to be active in the rec-assay but not in the Salmonella test. DNA-damaging activity was demonstrated to be due to the estragol component of the oil. Advantages of the combined use of these two short-term microbial assays in genotoxic studies are discussed.