Studies On Insecticidal Constituents Of The Endophytes F4-20 From Tripterygium Wilfordii

The strain F4-20, identified as the genus Streptomyces blastomycetica strain NRRL B-5480 strain NRRL B-5480, was isolated from the root of Tripterygium Wilferdii HooK.f., a medicinal plant in China by Research & Development Center of Biorational pesticide Northwest A&F University. In order to isolate alkaloids of Tripterygium wilfordii and other insecticidal activities, this paper did some research on the extraction, isolation, identification and biological activity of the fermentative product from F4-20. The results were as follows:The Wilforine and Wilforgine were demonstrated in the metabolic product of F4-20, using API HPLC/MS/MS, which showed that F4-20 can product the same metabolite as Tripterygium Wilferdii HooK.f, but it need to further verified.The insecticidal activity of the fermentative product from F4-20 was tested against Tetranychina harti(Ewing), Acyrthosiphon pisum(Harris), 3rd larva of Mythimna separata(Walker) and 3rd larva of Culex pipiens pallens with slide-dip method, leaf-dip method, and micro spot method. The result can been listed as below.(1)The intracellular crude extraction had obvious insecticidal activity against Tetranychina harti(Ewing), Acyrthosiphon pisum(Harris) and 3rd larva of Culex pipiens pallens. The LC50(24h) was 148.22, 232.39 and 15.67μg/mL, respectively.(2)The further study found that intracellular non-alkaloids of the four extractions had several insecticidal activity against Acyrthosiphon pisum(Harris) and 3rd larva of Culex pipiens pallens. The LC50(24h) was 98.09 and 11.15μg/mL, respectively. Besides The 100mg/mL of intracellular non-alkaloids was showed contact toxicity against 3rd larva of Mythimna separata(Walker). The corrected death rate was 99.73%, at 24 h. But extracellular alkaloids, extracellular non-alkaloids and intracellular alkaloids didn’t show obvious insecticidal activity.Totally, seven compounds were isolated from the fermentative product of F4-20 using chromatographic process and stracking activity method. And the structure of the seven compounds was identified as butyramide, Lup-20(29)-ene, 1-Octadecanoicacid, teleocidinB2, Cinnamic acid, α-D-threo-Hexopyranoside, dehydroxyaquayamycin B. Besides, dehydroxyaquayamycin B, a novel compound, was first isolated from the F4-20.The insecticidal activity of Cinnamic acid and dehydroxyaquayamycin B were tested in this paper. The result showed that Cinnamic acid had certain insecticidal activity against 3rd larva of Culex pipiens pallens,the LC50(24h) was 16.89μg/mL. And it also had certain insecticidal activity against Acyrthosiphon pisum(Harris). When the concentration was 0.1m/mL, the corrected death rate of 3rd larva of Culex pipiens pallens at 24 h was 86.97%.In summary, the chemical constituent of fermentative product from F4-20 was multiple, it was worth studying further.