木藜芦烷类化合物对萝卜蚜的生物活性及其构效关系

Insecticidal Activities of Grayane Diterpenoids from the Flowers of Rhododendron molle to Turnip Aphid and Their Structure-Activity Relationship

从高效杀虫植物闹羊花 (RhododendronmolleGDon)中分离获得 13个木藜芦烷类化合物 ,活性测定结果表明 ,化合物 1(RhodojaponinIII)和 6 (RhodomolleinI)对萝卜蚜无翅成蚜具有较高的忌避活性 ,以 2 0mg/L处理后 2 4h ,忌避率分别为 76 .6 4 %和 6 5 .0 6 % ,化合物 1、4 (RhodomolleinXVI)、6以 5mg/L处理后 ,与CK相比 ,试虫实验种群增殖倍数分别仅为 0 .2 1、0 .31和 0 .2 7;化合物 1、4、8(RhodomolinC)和 10 (RhodomoleinXVIII)浸叶饲喂法处理后 4 8h ,对萝卜蚜无翅成蚜的LC50 分别为 11.6 7、2 0 .14、2 4 .36、2 6 .92mg/L ,毒杀活性明显高于其他供试化合物。构效关系分析表明 ,保留C2 -C3 -环氧基 ,C6保留OH取代或降低其电子云密度 ,C10 保留单键取代基 ,C14 引入适当酯基或其他基团增加其电子云密度 ,均有利于提高其活性。

Thirteen grayane diterpenoids (1～13) were previousl y i solated from Rhododendron molle G Don. Results showed that compound 1(rhodoj aponin III) and 6(rhodomollein I) possessed higher deterrent activity to the win gless-adult of turnip aphid, Lipalus erysiml (Kaltenbach), with 76.64% and 65.06% of repellen rate 24 h after treatment with 20 mg/L, and compound 1, 4 (rh odomollein XVI) and 6 could reduce relative multiplication time of tested popula tion and got 0.21, 0.31 and 0.27 times of CK reproduction when female adult aphi d treated with 5 mg/L, respectively. Compound 1,4, 8 (rhodomolin C) and 10 (rhod omolein XVIII) possessed significant higher toxicity than other tested compounds and got 11.67, 20.14, 24.36 and 26.92 mg/L of LC 50 values against wingles s-adult aphid 48 h after treatment, respectively. Analysis on preliminary struc ture-activity relationship showed that substitute group of C 2-C 3-e poxy, C 6-OH, C 10 and C 14,which would was most important to ins ecticidal activity of grayanoid diterpenoids. Both reduce the density of electro n cloud in C 6 and increase that in C 14 would improve their bioactivi ty. Ring A and B may be necessary to maintain high activity in this kind of comp ounds. These results would give much valuable information to optimize the chemic al structure of grayane diterpenoids.