| The root bark of Tripterygium wilfordii Hook had been used for centuries by Chinese market gardeners to protect their crops against insect pest , it is one of widely used insecticidal plant in China . For the purpose of searching new environmental acceptable insecticides, active components , insecticidal activities , poisonous mechanism and formulation of Tripterygium wilfordii owere studied in this paper.1.Ten insecticidal constituents of T. wilfordii were isolated by means of phytochemistry combined with bioassay method. The structures of the compounds were determined by UV, IR, 'HNMR, "CNMR , 'H-'H COSY, 'H-'3C COSY , HMBC, HMQC and mass spectral analysis as triptophenolide methyl ether (LX-1), triptophenolide(LX-2), triptonide(LX-3), triptolide(LX-4), wilforlide A(LX-5), wilfordine(LX-6), euonine(LX-7), wilforgine(LX-8) and wilforine(LX-9) and 8-triptophenolide methyl ether(LX-11) .LX-11 is a new dipterpenoid compound. Laboratory bioassay showed the dipterenoids LX-3 and LX-4 had contact, stomach poisonous and antifeendant activities. The values of medium antifeeding concentration (AFC50) against the 4th larvae of Mythimna separata were 124. 06, 88. 63mg/L. Median stmoatch narcosis dose (ND50) were 66. 72, 38. 70ug/g. Median contact dose (LDJ were 2. 86,1.63ug/head, respectively. The alkaloids compounds LX-9, LX-6, LX-7, LX-8 had antifeedant, stmoatch narcosis activity, but no contact activity. The values of AFCa, were 30.85,40.17,53.22 and 77.15mg/L The NDb values were 20.67,82.70,1218.93,262.80 u g/g. The alkaloid compound LX-7 and dipternoid compounds LX-3, LX-4 were the first reported that had insecticidal activity , of which LX-3 and LX-4 were contact compoments of T. Wilfordii.2. The alkaloids and non-alkaloids of 71 wilfordii were extracted from the root bark of T. wilfordii and identified. The results of bioassay showed that the alkaloids had different insecticide activities with the non-alkaloids . The alkaloids and non-alkaloids from 71 wilfordii had antifeedant, toxicity and stomach narcosis activity .The values of AFC50 of the alkaloids and non-alkaloids against the 5th instars larvae of Pierisrapae , 3rd instars larvae of M. separata and Plutella xylostella were 70. 91, 39. 50, 1146. 82 and 99. 17, 47. 46, 1415. 90mg/L The LCSO values of poison were 36.52,13.69,102.99 and 72.79,53.87 , 1017.84mg/L. The LDSO values stomach narcosis to 5th instars larvae of Pier is rapae and Mythimna separata were 29.02,77.45 and 42. 26, 134. 48 n g/g. The alkaloids had no contact activity, but the non-alkaloids had. The medium contact dose (LD5<>) against 5th instars larval of P. rapae and M. separata were 3. 70, 3. 24 u g/head. When the concentration of them were 0. 5-20g/L, the unhatching of eggsratio was 34-60%.3. Triptolide is first found that had contact activity from T. wilfordii. The poisoned larvae of Mythimna separata became exciting, spasming , paralysising and finally dead.For the futher understanding the mechanism of action of triptolide on the molecular level and exploting the new environmental acceptable insectiides by means of biorational design, the mechanism of action of triptolide had also been studied in this paper. The activities of digestive enzymes of midgut of M. separata was examined with conventional biochemical methods, the results showed that the activities of protease, amylase and lipase of the poisoned larval midgut had no significant changes with the normal larval midgut ;The pathological changes were observed by electron microscope , the observation showed that the initial infected organellas were mitochondria. As the pathological process went on , the mitochondria had irregular enlarged, the bilayer membrane was not intact, the mitochondria critase was fuzziness;The cisterane of rough endoplasmic reticulum were enlarged, finally, vesiculation;LD compotely dissapper at the spasm .paralysis periods;The microvilli of the column cell and cotyloid cells had no changes.This suggested that the midgut cells were no the initalis target of triptoi...
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