Studies On Insecticidal Activity Of Terpinen-4-OL

Bioactive natural product model is a primary way to research and develop novel pesticides. Terpine-4-ol is a terpenoid compound existing in many plants, which showed high fumigation activity found by the Research and Development Center of Biorational Pesticides from essential oil of Sabina vulgaris Ant., and had been proved to be the main insecticidal composition of the oil, it is also friendly to environment and easily synthesized. So it would be a promising insecticidal lead coumpound. To further veritify the bioactivities and mechanism of Terpine-4-ol, the toxicity action against several normal insects were investigated under the laboratory conditions, toxicity symptom and pathological changes were observed and some effections of important physiological and biochemical criteria with insects were carried out. A series of derivatives were synthesized and the relationship between structures and insecticidal activities was analysised. The main results are given as follows:1. The insecticidal actions of terpiene-4-ol against insects included fumigation, repellent and contact, of which fumigation action was dominant. To 3rd-instar larvae of Plutella xylostella L., Mythima separata Walker and Heliothis armiera Hubner, LC50 values were 1.8321μL/L, 5.3473μL/L, 46.3801μL/L, respectively. The LC50 values were 2.9511μL/L, 27.9668μL/L, 136.4957μL/L against the adults of Musca domestiea L., Stitophilus zeamais Molschulsky, Tribolium castaneum Herbst.2. Different kinds of insects showed different types of symptom. When treated with terpiene-4-ol, the vivo symptom was charactered by a definite sequence of events, starting with excitation, convulsion, paralysis, and death. Plutella xylostella L., Mythima separata Walker, Heliothis armiera Hubner hyperemesised, recovery phenomenon was found in treated insects.3. Terpinen-4-ol could effect respiration in insects. After being disposed by terpiene-4-ol, insects showed higher respiration rate and variational respiratory quotient (RQ). The quantity of hemolymph in insects reduced. Compared with that of the untreated, the quantity in paralysis period reduced to 38.47%, the density of hemolymph increased, pH and osmotic pressure almost had no obviously changes.4. The observation of pathological changes under scanning-electron microscope showed that the pellet structure of the cuticle was destroyed, which might be correlated with water...