No abstract

The Essential Oils (EOs) from the leaves of species Cinnamomum verum J. Presl are used in the pharmaceutical industry for their numerous biological activities. Currently, the main compound of C. verum EO is eugenol which has acaricidal activity; however, a rare chemotype with benzyl benzoate as the main component can be found. Benzyl benzoate is recognized as an acaricide; however, studies of the C. verum EOs benzyl benzoate chemotype on Rhipicephalus microplus were not reported. The aim of this study was to evaluate the acaricide activity of an EO from a rare chemotype of C. verum, as well as purified benzyl benzoate, against larvae and engorged females of R. microplus resistant to amidines and pyrethroids. The EO was extracted from C. verum leaves and the compounds present were identified using a gas phase chromatograph coupled to a mass spectrometer. Efficacy against R. microplus was assessed by the larval packet and the engorged female immersion tests. A rare chemotype of C. verum was found to produce EOs with benzyl benzoate (65.4%) as the main compound. The C. verum essential oil was 3.3 times more efficient on the R. microplus larvae than was benzyl benzoate. However, no differences were found on the R. microplus engorged females. This is the first report regarding the acaricidal activity of C. verum with chemotype benzyl benzoate, and this compound showed acaricidal activity on R. microplus larvae.

No abstract

No abstract

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.