INSECTICIDAL AND GENOTOXIC ACTIVITIES OF OREGANO ESSENTIAL OILS

The essential oils (EOs) obtained from the oregano plants Origanum vul gare subsp. hirtum, Coridothymus capitatus, and Satureja thymbra were examined by a combination of GC and GC-MS and found to be rich in carv acrol, thymol, gamma-terpinene, and p-cymene. These EOs and their main constituents, carvacrol and thymol, were tested for insecticidal and genotoxic activities on Drosophila. The EO of S. thymbra was found to be the most effective as an insecticide, while carvacrol was found to be more toxic than thymol. The toxicities of carvacrol and thymol do n ot correspond to their participation in the EOs, and mixtures of these two phenols in levels resembling their content in the three oils show ed that the toxicity of carvacrol was reduced in the presence of thymo l, thus suggesting antagonistic phenomena. The somatic mutation and re combination test on Drosophila revealed that, among the five compounds studied, only thymol exhibits genotoxic activity.