Essential oil from Piper tuberculatum Jacq. (Piperaceae) and its majority compound β-caryophyllene: mechanism of larvicidal action against Aedes aegypti (Diptera: Culicidae) and selective toxicity.

Synthetic insecticides have been the primary approach in controlling Aedes aegypti; however, their indiscriminate use has led to the development of resistance and toxicity to non-target animals. In contrast, essential oils (EOs) are alternatives for vector control. This study investigated the mechanism of larvicidal action of the EO and β-caryophyllene from Piper tuberculatum against A. aegypti larvae, as well as evaluated the toxicity of both on non-target animals. The EO extracted from P. tuberculatum leaves was majority constituted of β-caryophyllene (54.8%). Both demonstrated larvicidal activity (LC₅₀ of 48.61 and 57.20 ppm, p < 0.05), acetylcholinesterase inhibition (IC₅₀ of 57.78 and 71.97 ppm), and an increase in the production of reactive oxygen and nitrogen species in larvae after exposure to the EO and β-caryophyllene. Furthermore, EO and β-caryophyllene demonstrate no toxicity to non-target animals Toxorhynchites haemorrhoidalis, Anisops bouvieri, and Diplonychus indicus (100% of survival rate), while the insecticide α-cypermethrin was highly toxic (100% of death). The results demonstrate that the EO from P. tuberculatum and β-caryophyllene are important larvicidal agents. [ABSTRACT FROM AUTHOR]