Studies On Chemical Constituents And Pesticidal Activity Of Scleroderma Citrinum Per

In the course of screening for naturally occurring insecticides from higher fungus in China, an extract of Scleroderma citrinum Per. was found to show insecticidal activity against Mythimna separate and Plutella xylostella. The pesticidal activities of extract from S. citrinum were determined; the isolation of insecticidal constituents in S. citrinum have been carried out. The main results are as follows. 1. The hypha growth inhibition of chloroform-methanol (1:1) extract from S. citrinum named total extract and it's petroleum ether, chloroform, n-butanol extract against 6 kinds of plant diseases were determined. At concentration of 1 mg/mL, the total extract and it's 3 kinds of extracts were inactive against Exserohilum turcicum and Alternaria solani; the inhibitory rates of the 4 kinds of extracts against Fusarium graminearum Schw were 60% to 70%. The inhibitory rates of n-butanol extract against Phytophthora capsici Leon. and Sclerotinia sclerotiorum (Lib.) de Bary were more than 85%. 2. The herbicidal activity of the total extract from S. citrinum and it's 3 kinds of extracts were determined in the seeds germination of Amaranthus retroflexus L. The results showed that the 4 kinds of extracts were inactive against A. retroflexus. At concentration of 12.5 mg/mL, the inhibitory rate of n-butanol extract against seed bourge of A. retroflexus was 63.2%, while the inhibitory rates of the other extracts against seed bourge, root and stem development of A. retroflexus were lower than 50%. 3. The antifeedant activity of the total extract from S. citrinum and it's 3 kinds of extracts against third-instar of Mythimna separate were determined. The results showed that the total extract and it's petroleum ether extract were very active, whose antifeeding rates in 48h were more than 80% at concentration of 25 mg/mL. The petroleum ether extract showed strong toxicity to the third-instar of M. separate with the corrected mortality of 80% in 48h at concentration of 10.0 mg/mL. 4. The antifeedant activity of the 9 fractions from petroleum ether extract after column chromatography against third-instar larvae of M. separate were determined. The results showed that fraction B was very toxic against third-instar larvae of M. separate with the mortality of 100% in 24h at concentration of 25 mg/mL. The antifeeding rates of fraction C, G, H and I were nearly or more than 70%. The contact toxicity of fraction B in 48h against third-instar larvae of M. separate was 86% at concentration of 12.5 mg/mL. 5. The contact toxicity of the 5 fractions from fraction B after column chromatography against third-instar larvae of M. separate were determined. The result showed that fraction B2 exhibited strong contact toxicity against the 3rd instar of Mythimna separate with the contact toxicity of 98% in 48h under the concentration of 5.0 mg/mL. At concentration of 10 mg/mL, the corrected mortality rate against Musca domestica L.was 80.4%, while B2 did not indicate contact toxicity against Plutella xylostella Linnaeus. 6. Six compounds W1-W6 were isolated from S. citrinum . Compounds W1 and W2 were not determined. At concentration of 5 mg/mL, Compounds W3,W4 and W6 showed low toxicity; The antifeedant activity of compond W5 was 40% and the contact toxicity of compond W5 was 20% in 48h against third-instar larvae of M. separate at concentration of 5 mg/mL.W3 and W5 were identified as ergosterol and hexadecanoic acid, respectively. The hexadecanoic acid was obtained from S. citrinum for the first time...