Studies On The Relationship Between The Structure And Insecticidal Activity Of Tutin

Coriaria sinica Maxim is used as an anti-flammary agant and a pesticide in the folk. The toxic contents of Coriaria sinica Maxim were characterized by Coriaria lactone. Professor Menglou Li's result proved that Coriaria lactone could be used to a new natural pesticide. This dissertation is involved the study on Coriaria lactone of the achenes of Coriaria sinica Maxim from Qinling, and studies the physiological mechanism of tutin and its acylation derivatives against insect by biological analysis. The main researches are as follows:1. Extraction and isolation of chemical constituents from Coriaria sinica MaximThree sesquiterpene lactones and one aroma compound were isolated from Coriaria sinica Maxim by using various chromatography and were structurally elucidated by the NMR, MS,IR,and UV spectra. Corianin was isolated from the achenes of this plant for the first time, and vanillin was isolated from this plant for the first time.2. The structural modification of tutinTo clarify their action mechanism and structure-effect relation further, some structural modification works on tutin have been done and three acylation derivatives were prepared. All of them were new compounds. Derivative A was 2-Benzoyltutin, derivative B was 2-iso- Butenoyltutin, and derivative C was 2-Chloroacetyltutin. The structure of them was identified by the NMR, MS,IR,and UV spectra. 3. The biological activity of tutin and its acylation derivativesTutin could affect feeding on larvae of Mythimna separate(Walker). The result showed that tutin had auxofeeding effect at the concentration of 0.25mg/mL, but tutin could obviously characterized antifeeding effect at the concentration of 0.5mg/mL, and its antifeeding rate was higher when the concentration increased. The antifeeding effect was the most stable at the concentration of 4.00mg/mL, its antifeeding rate kept in 40%.The applicability against tutin was different when instar of larvae of Mythimna separate (Walker) changed, the adaptability decreased when its instar increased. Third instar larvae of Mythimna separate(Walker) performed good antifeeding activity when it was fed leaf disk with tutin at beginning, but it kept declining in the following times, the antifeedant rate declined 44.25% at 48h. The antifeeding activity of tutin against forth instar larvae of Mythimna separate (Walker) increased slowly, but it kept high against fifth instar larvae.The contrast of biological activity among tutin and its acylation derivatives were different. The antifeeding activity of three new derivatives was higher than tutin and the most potent was 2-iso-butenoyltutin (B), the treated insects appeared toxic symptoms like paralysis and coma and died at 32h, 40h and 48h respectively, the total death rate was 9.3%. The biological activity test showed that acylation derivatives of tutin had higher activities than tutin on blood sugar content, protein content of midgu and esterase activity of Mythimna separate. 2-iso- butenoyltutin (B) had the most obvious effect of biological activity in the four compounds. Tutin and its acylation derivatives A and C inhibited the activity of SOD and POD, acylation derivatives B inhibited the activity of POD, but activated SOD, made the defense enzymes system disorder and exerted toxicity effect.In conclusion, the biological activity of tutin's acylation derivatives was higher than tutin. The most potent was 2-iso-butenoyltutin (B), which was the best structure and could be the new lead compound of pesticide.