Toxicological Effects of Compounds from the Leaves of Schinus terebinthifolius Against Two Tetranychid Mites (Acari: Tetranychidae)

Abstract

The use of synthetic acaricides is becoming increasingly hazardous to non-target organisms. Plant-derived natural products are alternative candidates with general low toxicity to human and environment.  Two extracts and nine phenolic compounds (1-9) from the leaves of the Brazilian pepper tree (Schinus terebinthifolius Raddi) were investigated for their acaricidal effects against two tetranychid mites, Tetranychus cinnabarinus (carmine spider mite) and Tetranychus urticae (two-spotted spider mite). After 7-days of treatment, the ethyl acetate fraction demonstrated remarkable mortality against T. cinnabarinus (86.67%) while, the n-hexane fraction showed the highest mortality against T. urticae (96.67%) at 200 μg/mL. Among the tested compounds, afzelin (2) and protocatechuic acid (7) exhibited remarkable activity. Regarding T. cinnabarinus, afzelin showed the highest mortality (86.67%), toxic activity (LC50 22.32 μg/mL and toxicity index, Ti 0.972), and the fastest lethality by time. Whereas, protocatechuic acid achieved the highest mortality (96.67%), the lowest LC50 (0.232 μg/mL, Ti 73.71), and fastest lethality by time against T. urticae. This study reported a promising in vitro acaricidal activity of the phytoconstituents of the Brazilian pepper tree and suggested its isolated compounds, such as afzelin and chatechuic acid, as alternative leads for the development of echo-friendly acaricides.