Acaricide activity of different extracts from Piper tuberculatum fruits against Rhipicephalus microplus.

Rhipicephalus microplus is the main tick that affects cattle. Plant bioactive molecules can be used to control this ectoparasite. The aim of this study was to evaluate the in vitro efficacy of Piper tuberculatum fruit extracts obtained with different solvents on R. microplus larvae and engorged females. Hexane, ethyl ether, ethanolic, and methanolic extracts of P. tuberculatum fruits were evaluated. After extraction, all of the extracts were dried. Adult immersion tests and larval packet tests were performed with five different concentrations of each of the extracts. The hexane extracts of P. tuberculatum showed the highest larvicidal activity against R. microplus (lethal concentration (LC50 = 0.04 mg/mL), followed by the ethyl ether (LC50 = 0.08 mg/mL), ethanolic (LC50 = 2.73 mg/mL), and methanolic (LC50 = 4.49 mg/mL) extracts. The P. tuberculatum fruit extracts were also effective against R. microplus-engorged females. Ethyl acetate extracts showed the highest efficiency (LC50 = 18.4 mg/mL), followed by the methanolic (LC50 = 105.6 mg/mL), ethanolic (LC50 = 140.0 mg/mL), and hexane (LC50 = 297.4 mg/mL) extracts. All of the extracts showed similar chromatographic profiles containing 24% piperine. The P. tuberculatum fruit extracts contain bioactive compounds with great potential to improve the standard formulations of acaricides for the control of R. microplus.