Trace Insecticidal Active Constituents From Pharbitis Purpurea (L.)Voigh And Study On Its Application

It is a focus on the study of botanical pesticides to find bio-active natural products from plant, it is very interesting to isolate these compounds and to make use of them as new agrochemical or leading structure for new agrochemicals. For the purpose of searching new environmental acceptable insecticides, extracts from 15 plant species were tested for their insecticidal activities. Active components, insecticidal activities and application of Pharbitis purpurea (L.) Voight were studied.Use methanol, acetone, petroleum, chloroform, n-hexane and water to extract 15 plant species, and the extracts were tested for their insecticidal activities against Plutella xylostella L. by means of direct contact, stomach poison and poison method. The result showed that semen pharbitidis possessed the highest activities.Insecticidal activities of extracts by different solvents from different parts of Pharbitis purpurea (L.) Voight were tested against P. xylostell, Mythimna separate Walker and Spodoptera exigua Hubner, semen pharbitidis demonstrated the highest activities against 3rd instar P. xylostel. Semen pharbitidis was extracted by methanol, acetone, petroleum, chloroform, n-hexane and water respectively, and the antifeedant, contacting, stomach poisonous, oviposition and inhibiting growth activities of six extracts against 3rd instar P. xylostell were tested, six extracts possessed different bioactive. Methanol extract showed the greatest activities mainly in anti-feeding, contacting and inhibiting growth activities. The values of medium antifeeding concentration (AFC50) were 34.60g/l in 48 hours, and median contact dose (LD50) were 0.01528mg/head in 72 hours, methanol extract demonstrated 100.00% mortality at 0.1gDW/ml concentration, methanol exact also showed obvious growth inhibiting which provided 101.55% and 31.16% inhibiting rate after lday and 2 days at 0.05gDW/ml concentration, respectively, and the pupation rate was just 8.00% which was significantly lower compared with the control. Besides, methanol extract also showed high ovicidal activity against P. xylostel. Over 80% ova didn't incubate after treated, while water extract possessed no ovicidal activity.Methanol extract of semen pharbitidis were isolated by means of phytochemistry combined with bioassy. Methanol extract were continuously extracted by petroleum, chloroform, ethyl acetate and n-butyl alcohol, and n-butyl alcohol extract possessed the highest activities. The values of medium antifeeding concentration (AFC50) of n-butyl alcohol extract against 3rd instar P. xylosiella was 1.7473g/l in the condition of no-choice after 48 hours, and mediun contact dose (LD50) were 0.01740mg /head , and n-butyl alcohol extract also showed obvious growth inhibiting which provided 39.51% and 55.38% inhibiting rate after lday and 2 days, respectively, and the pupation rate was just 14.00% that was significantly lower compared with the control.The n-butyl alcohol extract was isolated and purified by column chromatography and thin-layer chromatography (TLC), and fifteen samples were put up together, and EPN1 and EPN3 demonstrated high contact activity, the values of LD50 were 0.0090mg/head and 0.0103mg/head in 72 hours. EPN1 was isolated through HPLC and determined by LC-MS. Lysergol, chanoclavine and agroclarine alkaloids that had been reported existed in semen pharbitidis from documents were not found in...