Chemical composition, toxicity and acetylcholinesterase inhibitory activity of Salvia officinalis essential oils against Tribolium confusum

Abstract

The present study was aimed to evaluate the contact toxicity of Salvia officinalis essential oils against Tribolium confusum. Essential oils were obtained by Clevenger-type water distillation and their contact toxicities were tested at concentrations of 0.06, 0.12, 0.25 and 0.5 µL/cm2. β-Thujone (20.1%), 1,8-Cineole (15.91%), Camphor (14.79%) and Viridiflorol (9.06%) were determined to be the major constituents of the oil. Biotests showed that essential oils exhibited contact toxicity against T. confusum larvae and adults with median lethal concentrations values of 0.13 and 0.16 µL/cm2, respectively after 7 days of treatment. Toxicity was also demonstrated by a significant repellent activity in binary choice bioassays. Results showed that essential oils caused significant inhibition in the acetylcholinesterase activity with a dose-response relationship. The highest concentration used (0.5 µL/cm2) was the most effective inhibitor of T. confusum AChE activity (59.88 ± 4.71%) after 72 h of exposure.