Effect of ethanolic extract of Capsicum frutescens L. on adult female of Rhipicephalus microplus (Ixodidae).

This study evaluated the effects of ethanol extract of Capsicum frutescens L. (Solanaceae), colloquially known as malagueta pepper, on egg production and hatching rate of larvae of Rhipicephalus microplus. Plant samples were collected in Montes Claros, Minas Gerais, Brazil. Selected mature fruits were washed, dehydrated in a forced air oven at 40 ± 5 °C to constant weight. The material was incubated in absolute ethanol during 10 days, and the extract was filtered, dried, and stored in amber vials under refrigeration at 4 °C. Engorged adult female ticks were immersed in 10 ml solutions of ethanol extracts at 25, 50, 75, 100, or 150 mg ml(-1) dry matter, solubilized in dimethyl sulfoxide (DMSO) at 1% v/v. These concentrations were compared to distilled water or 1% v/v DMSO in distilled water as negative controls and a commercial product as positive control. The extract resulted in significantly lower oviposition at all tested concentrations when compared to the negative controls. On days 2 and 3 posttreatment, mortality rates of female ticks ≥55% were observed for concentrations ≥75 mg ml(-1). These concentrations resulted in a significantly lower hatchability mean, and the LC90 on hatching inhibition of R. microplus, estimated by probit analysis, was 91.8 mg  ml(-1). High acaricidal in vitro effect was verified, and toxicological tests and analyses in vivo are important to determine appropriate dosages and frequency of the application necessary to promote this extract as safe and effective alternative for control of R. microplus.