Chemical composition of essential oils of different Siparuna guianensis chemotypes and their acaricidal activity against Rhipicephalus microplus (Acari: Ixodidae): influence of α-bisabolol

ABSTRACT

In the present study, chemical characterization of essential oils (EOs) from different chemotypes of Siparuna guianensis was performed and their acaricidal activity against Rhipicephalus microplus evaluated. Leaves of S. guianensis were collected from three municipalities of the Zona da Mata region, Minas Gerais State, Brazil: São Miguel do Anta (SMA), Tocantins (TO), and Viçosa (VI). The EOs chemical compositions were analysed using gas chromatography-mass spectrometry. To evaluate acaricidal activity, larval packet tests (LPT), and adult immersion tests (AIT), were used. The major compound found in the SMA and TO samples was α-bisabolol (62.6 and 48.1%, respectively). In the VI sample, germacrene D was the predominant compound (25%). In the LPT, the highest concentration (20 mg/mL) of the VI sample caused a mortality rate of 81.1%, while for the TO and SMA samples, mortality was 100%. Pure α-bisabolol, acaused 100% mortality at a concentration of 10 mg/mL. The control percentage at the highest concentration (60 mg/mL) was 77.4, 87.8, and 98.6%, for the TO, SMA, and α-bisabolol samples, respectively. We demonstrate that there is variation in the chemical composition of the EOs of S. guianensis from different regions, and that the chemotypes rich in α-bisabolol presented greater activity against R. microplus.

KEYWORDS:

• Cattle tick
• botanical acaricidal
• negramina
• sesquiterpene
• α-bisabolol

Acknowledgments

We thank the CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) for financial support (project financing, scholarships and grants) and for the grants PQ to CMO. Monteiro (311889/2017-4). This study also was financed (through scholarships) in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil (CAPES), Finance Code 001. We thank Dr. Ariane Luna Peixoto of the Research Institute of the Botanical Garden of Rio de Janeiro, Brazil for the identification of samples of S. guianensis, and Dr. Márcia Cristina de Azevedo Prata and Dr. John Furlong for providing the ticks.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by “Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil (CAPES), Finance Code 001 and “Conselho Nacional de Desenvolvimento Científico eTecnólogico” [CNPq Process number #311889/2017-4].