Bioactivity of Meliaceae, Amaryllidaceae, Solanaceae and Amaranthaceae plant aqueous extracts against the cattle tick Rhipicephalus microplus .

Commercial synthetic acaricides have selected resistant populations of Rhipicephalus microplus , and generate residues in the environment or in milk/cattle products. In this study, aqueous extracts (AE) from Melia azedarach (Maz), Allium sativum , Capsicum chinense , Nicotiana tabacum (Nta) and Dysphania ambrosioides were evaluated for the bioactivity against the cattle tick. The treatment using Nta or Maz AE resulted in the lowest egg hatching rate (34.0 ± 11% and 25.0 ± 19%), and in the values of reproduction inhibition ranging from 89.0% to 85.3%. Phytochemical screening associated to RP-HPLC/DAD analysis suggested the presence of alkaloids for Nta and gallic acid derivatives and catechins, for Maz. Such results highlighted that the use of Nta and Maz AE can be a promising source of bioactive compounds for the control of infections caused by the cattle tick.