Genotoxic and mutagenic effects of permethrin in mice: micronuclei analysis in peripheral blood erythrocytes.

Pyrethroids such as permethrin are synthetic compounds widely used in the agriculture of many countries to combat plagues and in domestic products, such as acaricides. Not so long ago these chemicals were characterized as non-toxic for non-target organisms; however, recent studies have showed that these compounds could present toxic potential for many organisms. In this sense, this study presents genotoxic and mutagenic potential of permethrin administered intraperitoneally in mice under artificial conditions by the use of micronucleus assay in the peripheral blood of these animals. The mice were divided into five groups: group I = negative control (distilled water), group II = positive control (cyclophosphamide), group III = 30% of permethrin LD(50) (96 mg/kg), group IV = 50% of permethrin LD(50) (160 mg/kg), and group V = 80% of permethrin LD(50) (256 mg/kg). The peripheral blood was collected 24, 48, and 72 h after treatment. Results showed that all the tested permethrin dosages presented genotoxic and mutagenic effects 24 h after treatment, which would contradict the classification of this chemical product as moderately toxic, i.e., unable to cause damages to the cell DNA.

Acaricidal activity of ethanolic extract from aerial parts of Tagetes patula L. (Asteraceae) against larvae and engorged adult females of Rhipicephalus sanguineus (Latreille, 1806).

BACKGROUND: The tick Rhipicephalus sanguineus is the species with the largest worldwide distribution and is proven to be involved in the transmission of pathogens such as Babesia canis, Ehrlichia canis, Coxiella burnetii, Rickettsia ricketsii, Rickettsia conorii, among others. Studies have demonstrated acquisition of resistance to some of the active principles used in commercial formulations of acaricides. Tagetes patula (Asteraceae) is a plant with highlighted economic and commercial importance due to the production of secondary metabolites with insecticide and acaricide potential, mainly flavonoids, thiophenes and terpenes. METHODS: The in vitro acaricide action of the ethanolic 70% extract from aerial parts of T. patula, obtained by percolation, was evaluated against larvae and engorged adult females of Rhipicephalus sanguineus by immersion test for 5 minutes. The chemical characterization of this extract was done by liquid chromatography coupled with mass spectrometry (LC-MS), using direct injection of sample. RESULTS: Despite T. patula not proving lethal to adults in any of the concentrations tested, at 50.0 mg/mL oviposition rate decreased by 21.5% and eliminated 99.78% of the larvae. Also it was determined that the best results were obtained with 5 minutes of immersion. From the chromatographic analysis twelve O-glycosylated flavonoids were identified. CONCLUSIONS: This is the first report on the acaricidal activity of T. patula extract against Rh. sanguineus. If we consider the application of the product in the environment, we could completely eliminate the larval stage of development of the ixodid Rh. sanguineus.