Acaricidal activity of leaves of Morus nigra against the cattle tick Rhipicephalus microplus / Atividade acaricida das folhas de Morus nigra em carrapato Rhipicephalus microplus

The acaricidal activity of crude ethanolic extract and fractions from the leaves of Morus nigra (Moraceae) was carried out on female cattle ticks Rhipicephalus microplus, using the adult immersion test. The mortality and fertility of females exposed to different concentrations of hexane, chloroform and ethyl acetate fractions, as well as ethanolic extract of M. nigra with concentrations of 5, 10 and 25mg/ml were evaluated using three treatment groups, two control groups and triplicate tests. The study also identified the main phenolic compounds of the extract and fractions of this species by HPLC. The chloroform fraction of leaves of M. nigra (25mg/mL) showed the best results for this species, obtaining 62.6% of inhibition of oviposition, 39.3% of eggs eclosion average and 65.4% of effectiveness. HPLC analysis revealed the presence of phenolic compounds, which may be related to biological activity shown by the extracts, which can be used as an alternative control against R. microplus adult tick.(AU)

A atividade acaricida do extrato etanólico bruto e das frações das folhas de Morus nigra (Moraceae) foi avaliada no carrapato Rhipicephalus microplus, utilizando-se o teste de imersão de fêmeas ingurgitadas. Foram avaliadas a mortalidade e a fertilidade das fêmeas ingurgitadas, expostas a diferentes concentrações (5, 10 e 25 mg/mL) das frações hexânica, clorofórmica e acetato de etila, bem como do extrato etanólico. Os testes foram realizados em triplicata. O estudo também identificou os principais compostos fenólicos do extrato e das frações dessa espécie por HPLC. A fração clorofórmica das folhas de M. nigra (25mg/mL) apresentou o melhor resultado para essa espécie, obtendo-se 62,6% de inibição da oviposição, 39,3% da eclosão dos ovos e 65,4% de eficácia. A análise por HPLC revelou a presença de compostos fenólicos, os quais podem estar relacionados com a atividade biológica demonstrada pelos extratos, que podem ser utilizados como auxiliar no controle contra carrapato adulto de R. microplus.(AU)

Acaricidal activity of extracts from the leaves and aerial parts of Neoglaziovia variegata (Bromeliaceae) on the cattle tick Rhipicephalus (Boophilus) microplus.

This experiment was carried out to study the bioacaricidal activity of Neoglaziovia variegata against engorged females of Rhipicephalus (Boophilus) microplus. The mortality and fecundity of groups of engorged adult females exposed to different concentrations of ethanol, hexane, chloroform, and ethyl acetate extracts obtained from the leaves and aerial parts of N. variegata were evaluated, using three treatments with concentrations of 5, 10 e 25 mg/ml; two controls (distilled water and distilled water with drops of cremophor); with three replicates. The hexane extract of the leaves demonstrated significant results, presenting 94.1% inhibition of oviposition; 0.33% the average percentage of eclosion of eggs; and 99.8% of effectiveness. These results indicate N. variegata, particularly the hexane extract of leaves, as potential alternative control agents of R. (B.) microplus. Pharmacological and chemical studies are continuing in order to characterize the mechanism responsible for this effect.