Bioactivities And Insecticidal Mechanism Of Four Kinds Of Terpene Monomers Against Zophobas Morio

Zophobas morio is a kind of easy breeding, no-drug resistance, having a strong antioxidant activity insects. It often used as an experimental material in insect biology, morphology, taxonomy, enzymology and environmental science and other aspects. Along with the attention enhancement on the ecological environment and the quality improvement of people’s life, most countries in the world are studying pesticide in place of chemical agent. The active ingredients of plant pesticide, naturally present in the plant, have a good compatibility with the environment, so botanical pesticides have become the focus of research in the world. The plants contain a variety of substances having biological activity, wherein the terpene is a class of compounds with more content. At home and abroad for now, research on terpene focuses primarily on the separation of components, the structure determination and the biological activity. The paper selected the four kinds of terpene monomers including α-terpineol, β-pinene, α-pinene and1,8-cineole as the test chemical, the4th instar larvae of Zophobas morio in this experiment were used with the objects on determining the acute toxicity. It talks about the effects of the four kinds of terpene monomers on protective enzymes, detoxifying enzymes and acetylcholine enzymes activity in the4th instar larvae of Zophobas morio for the first time. So as to study the insecticidal mechanism of the four kinds of terpene monomers and provide a theoretical basis for exploration of environment friendly, efficient and safe new botanical insecticides.It determined the acute toxicity of the four kinds of terpene monomers against the4th instar larvae of Zophobas morio in a gas-fumigation system. The results showed that LC50range of α-terpineol, β-pinene, α-pinene, and1,8-cineole against the4th instar larvae in acute toxicity test at48h after fumigation were6-70ug/L. The miximum LC50values is1,8-cineole and the LC50is6.505μg/L. The maximum LC50values is a-terpineol and the LC50is69.425μg/L. α-Terpineol, β-pinene, α-pinene and1,8-cineole had high biological activity on Zophobas morio. The four kinds of terpene monomers’ cytotoxicity were stronger with the prolonging of time.In order to study the toxicity mechanism of α-terpineol. β-pinene. a-pinene and1,8-cineole, we tested the in vivo activities of protective enzymes, detoxification enzymes and acetylcholinesterase enzymes of the LC50and LC20concentrations monomers against the4th instar larvae using biochemical methods. The results showed that LC50and LC20concentrations of the four kinds of terpene monomers can effectively interference the protective enzymes, detoxifying enzymes and acetylcholine enzymes activity. Under the fumigation at two concentrations (LC50and LC20) of a-terpineol, β-pinene, α-pinene and1,8-cineole, the activities of the carboxylesterase (CarE) and the acetylcholinesterase (AchE) was inhibition. The acid phosphatase (ACP) was increase. The alkaline phosphatase (ALP), the glutathione-s-transferase (GSTs) and the catalase (CAT) showed first increase and then inhibition. Under the fumigation at two concentrations of α-terpineol, α-pinene and1,8-cineole, the activities of the superoxide dismutase (SOD) and the peroxidase (POD) showed first increase and then inhibition. Under the fumigation at two concentrations of β-pinene, the activities of the superoxide dismutase (SOD) and the peroxidase (POD) showed inhibition.Through the above-described test results show that α-terpineol, β-pinene, α-pinene and1,8-cineole had high biological activity on Zophobas morio, which could effectively interference the main protective enzymes, detoxifying enzymes and acetylcholinesterase enzymes, disrupt the normal physiological metabolism and show high toxicity effect. The four kinds of terpene monomers is the active ingredient having biological activity in the plants, which have a higher toxicity on insects, and it can interference the main enzymes of insects in vivo. It has high research value and broad development and utilization prospects in pest prevention and control field.