Abstract: 【Aim】 Isolating insecticidal activities compounds is an important method to discover new pesticides. 【Methods】 Insecticidal activities and active ingredients of Tripterygium hypoglaucum against six lepidopteran insects were studied with bioassay-guided fractionation methods. 【Results】 The results showed the petroleum extract, methanol extract and acetic ether extract of the root of T. hypoglaucum had antifeedant activity against the 3th instar larvae of Mythimna separate Walker, with the AFC₅₀  value 1 165.7 μg/mL, 104.3 μg/mL and 47.3 μg/mL 24 h after treatment, respectively. The methanol extract of the root bark had contact toxicity to the 4th instar larvae of M. separatar, with the LD₅₀ values 100.4μg/larva 24 h after treatment. Four sesquiterpenes pyridine alkaloids, i.e., wilfortrine, wilforgine, wilfordine and wilforine, were isolated from the methanol extract of the root bark of T. hypoglaucum by bioassay-guided fractionation. The bioassay results showed that wilfortrine and wilforgine had stomach toxicity with the ND₅₀ value 18.1 μg/larva and 7.4 μg/larva,  respectively against M. separata； wilfordine and wilforine had topical toxicity with the ND₅₀ value 0.33 μg/larva and 0.06 μg/larva, respectively against M. separata and stomach toxicity with the ND₅₀ value 5.62 μg/larva and 1.24 μg/larva,  respectively against Agrotis ypsilon. 【Conclusions】 T. hypoglaucum exhibited insecticidal activity of some degree against the all six lepidopteran insects tested, and the main active ingredients were wilfortrine, wilforgine, wilfordine and wilforine.

Key words: Tripterygium hypoglaucum, insecticidal activity, sesquiterpenes pyridine alkaloids