---

Introduction: In this study, antimutagenesis effect of ethanolic extract of propolis by Ames test against two mutagenic substances named azide sodium and potassium permanganate in the presence and the absence of microsomal homogenate of mouse liver (S9) has been investigated. Materials and Methods: In this experimental study at first, different concentrations of ethanolic extract of propolis (0.1-5%) for determining minimum inhibitory concentration (MIC) against tester strains were used. Then by Ames test, antimutagenesis effect was assessed in nontoxic extent. In this test, various strains of Salmonella typhymurium (TA100 and TA97) that contained selective mutation in their operon histidine, were used. Mutant strains (His-) were grown on culture media containing minimum salt and glucose in the presence of mutagen substances above. So only those bacteria that were reversed by mutation (His+) could grow and form colonies on culture media. If antimutagen (EEP) and mutagen substances were gathered, reversed mutation would be reduced and the rate of mutation inhibition could be calculated by means of formula. The differences between the averages of revertants per plate of the sample in relation to the mutagens were analyzed using SPSS software and one-way ANOVA. Results: The resulted MIC values clearly showed that ethanolic extract of propolis at 5% concentration has antibacterial activity against Salmonella typhymurium, but in 0.1-4% concentrations, such effects were not seen. Findings also showed that propolis in such concentrations could neutralize mutagenic effects of those substances in a dose dependent manner. Conclusion: Finally we found that ethanolic extract of propolis that contains different kinds of major and important substances like flavonoids, has good antimutagenic effects and the best concentration for obtaining such effect is in 4% which also was confirmed with microsomal results. The mechanism of antibacterial effect of propolis is complex and it has no analogy to any classic antibiotics, but it should be emphasized that bacterial cell division is inhibited by propolis. Some researchers also argue that propolis could inhibit DNA-dependent RNA polymerase.

---

Background: Nowadays, cancer is one of the main causes of death in the world and mutagens cause death in millions of patients. Noticing the side effects of the drugs used to treat cancer, scientists are looking for drugs with fewer side effects and more therapeutic effects. Accordingly, the number of studies in this field is rapidly increasing. This study was done to evaluate the effects of antimutagenesis of aqueous and alcoholic extracts of A. vera leaf gel and latex by Ames test against the mutagenic substance named sodium azid in the presence and absence of microsomal homogenates of rat liver (S9). Materials and Methods:In this experimental study, after preparing different extracts of A. vera gel and latex, the antimutagenic effect of different extracts was assessed by Ames test, within which a mutant strain was grown on a culture containing mutagen substance (NaN3). Antimutagen (A. vera extract) reduced reversed mutation. The difference between the mean number of revertants per plate in relation to the mutagens was analyzed through one-way ANOVA using SPSS software. Results: The results showed that the ethanol extract of latex and aqueous extract of gel had the maximum (91%) and minimum (56%) percentages of inhibition, respectively. Conclusion: This assessment revealed strong antimutagenicity effect for all of the extracts due to the presence of different kinds of antioxidants substances such as various anthraquinones, flavonoids, and vitamins A, C, and E. The maximum inhibition of mutation was observed in ethanol extract of latex. This observation supports the results obtained from the application of microsome mixture as well as those reported by other researchers.

---

Background: Avicennia marina (Forssk.) Vireh. or gray mangrove tree, belonging to the family Avicenniaceae, has long been used as a remedy to treat ulcers and skin diseases. In the present study, the antimutagenic activities of young and mature leaf extracts of Avicennia marina against the mutated bacterium Salmonella typhimurium TA100 were investigated. Materials and Methods: In this experimental study, the bacterial strain was checked for the intended genotypes. Leaves were isolated, dried, and chopped finely using a blender and they were extracted with 80% ethanol or water using a Soxhlet extractor. Metabolic activation was prepared from male rat homogenized liver. Antimutagenic effect of the extracts was tested using Ames test in the presence of a mutagen. Results: The number of mutant colonies decreased in the presence of both ethanol and water extracts with (+S9) and without (-S9) metabolic activation. The ethanolic extract exhibited a higher antimutagenic activity than the water extract. There were no inter-assay differences in the presence and absence of the S9 mixture. The highest (71%) and the lowest (24%) inhibition rates of Salmonella typhimurium TA100 bacterial growth were observed with the ethanolic extract of mature leaves from Bordekhon region and the aqueous extract of young leaves from Assaluyeh region, respectively. Conclusion: The findings of the present study suggest that Avicennia marina (Forssk) Vireh. leaf extracts may contain bioactive compounds that can inhibit mutation, and that biotic and/or abiotic stress might have an effect on the antimutagenic potential of these leaf extracts in the two regions.