QSAR of genotoxic active benzazoles.

Previously synthesized 2,5-disubstituted benzoxazole and benzimidazole derivatives, were tested for their genotoxic activity in the Bacillus subtilis rec- assay. The results revealed that 5-methyl-2-(p-aminobenzyl)benzoxazole exhibited the highest genotoxic response, which was comparable to 4-nitroquinoline 1-oxide (4-NQO), the reference agent of classical positive mutagen. Among the other tested compounds, four showed a genotoxic activity. A QSAR study revealed that structural parameters IY(C(2)H(4)) and IY(CH(2)O), indicating the bridge elements between the phenyl moiety and the fused ring system at position 2 and the quantum chemical parameter (DeltaE ), showing the difference between HOMO and LUMO energies, were found significant for enhancing the genotoxic activity in these compounds. In addition, the substituent effects on positions R and R(1) were found important for the activity as well as holding a substituent possessing a maximum length with a minimum width property on position R(1) like alkyl groups. On the other hand, substituting position R with an electron donating group instead of electron withdrawing group increased the genotoxic activity.

Synthesis, characterization and mutagenicity of new cis-[Pt(2-substituted-benzimidazole)2Cl2] complexes.

In this study, four new platinum(II) complexes with the structures cis-[Pt(Ligand)2Cl2] (ligand = 2-(p-methoxy-/or-p-chlorobenzyl or p-methoxyphenyl)benzimidazol (1, 2, 4 respectively) and 5(6)-methyl-2-phenoxymethylbenzimidazole (3) were synthesized and characterized by their elemental analysis, and IR and 1H NMR spectra. The potentials of the Pt(II) complexes for short-term bacterial mutagenicity were tested in reverse-mutation assays using Salmonella typhimurium frame-shift strain T 98 and S. typhimurium TA 100 and TA 102 strains, which carry mutations particularly sensitive to reversion by DNA base-pair substitution. The tests were performed in the absence of S9 rat liver fraction. Among the complexes tested 1 had no mutagenic activity. Complex 4 was found to be weakly mutagenic in TA 98 only. The Pt(II) complexes 2 and 3 were found to be mutagenic in TA 98, TA 100 and TA 102.

Synthesis, characterization and in vitro cytotoxic, mutagenic and antimicrobial activity of platinum(II) complexes with substituted benzimidazole ligands.

In this study, six Pt(II) complexes bearing 5(6)-H or -CH(3)-2-phenyl or -(2'-pyridyl) or -mercaptomethylbenzimidazole ligands as 'carrier groups' were synthesized and characterized by elemental analysis, IR and (1)H-NMR spectra and evaluated for their preliminary in vitro cytotoxic activity to the human RD Rhabdomyosarcoma cell line and mutagenic properties in Salmonella typhimurium strains TA 98 and TA 100 in the absence of the S9 rat liver fraction. The preliminary test results showed that the complexes had slightly greater cytotoxic activity on the RD cell line at 1 microM concentration than cisplatin. Among the compounds tested for their mutagenicity, Pt(II) complexes of 2-(2'-pyridyl)- and 5(6)-methyl-2-(2'-pyridyl)benzimidazoles were found to be mutagenic. A comparative study of the MIC (minimum inhibitory concentration) values indicated that, in general, there were no differences between the poor antimicrobial activity values of the ligands and their Pt(II) complexes with respect to the tested microorganisms. These results suggest that the synthesized Pt(II) complexes should be considered for further antitumor activity studies.

Age-related activity of catalase in different genotypes of Drosophila melanogaster.

The enzyme catalase protects aerobic organisms from oxygen free radical damage by converting hydrogen peroxide to molecular oxygen and water before it can decompose to form the highly reactive hydroxyl radical. This damage has been implicated in the increased risk of disease and death associated with aging. In order to study the age-specific activity of catalase in male D. melanogaster, three different genotypes (Oregon w.t., ebony mutant, and the F1 hybrids of the two), whose mean life spans are about 55, 40, and 63 days, respectively, were used in the experiments. As the mean life span of the mutant is the shortest the enzyme activity was measured until the 43rd day, whereas in Oregon w.t., it continued until the 72nd day and in hybrids until the 79th day (longest-lived group). Although the enzyme activity in mutant flies increased sharply till the 9th day (and attained the highest level), later it declined sharply. In the other genotypes, the enzyme activity increased gradually until the 20-25th days, and then declined steadily in comparison to that of the ebony mutant. We found that higher catalase activity is associated with reduced life span for ebony mutant. It is obvious that some relationship exists between life span and antioxidant enzymes; however, a review of the literature does not at the moment allow as to understand the underlying mechanism involved in aging.

[The mutagenicity of some insecticides in the Salmonella/microsome test system]. / Salmonell/mikrozom test sistemi ile bazi insektisitlerin mutajeniteleri üzerine bir çalisma.

The mutagenic effects of 4 insecticides, i.e., bioallethrin, tetramethrin, propoxur, lethane and three commercial formulation of insecticides i.e. asbo, formulation I, formulation II was determined in a standard Salmonella typhimurium assay with the use of strains TA 98 and TA 100. Bioallethrin was found to be a weak mutagen in the TA 100 and TA 98 strains of S. typhimurium, whereas propoxur, formulation I showed weak mutagenic effects only on S. typhimurium TA 98 strain.

[Mutagenicity testing of some azo dyes used as food additives]. / Gidalara katilan bazi azo boyalarinin mutajenik etkilerinin test edilmesi.

The mutagenicity of 4 azo dyes (Ponceau 4R, Amaranth, Sunset Yellow FCF and Tartrazine) that are widely used to color food has been evaluated. They were tested for mutagenicity in the Salmonella typhimurium plate-incorporation and preincubation assays. The standard plate-incorporation and preincubation assays performed directly on the dyes in the absence and presence of rat-liver S9. No mutagenic activity was seen for any of the azo dyes tested by using the standard tester strains, TA 98 and TA 100.