Study On The Chemical Components And Biological Activity Of One Chaetomium Sp. Strain

One endophytic fungi strain which can produce abundant secondary metabolites was screened out by chemical screening from 61 strains of Chaetomium sp. from Ginkgo biloba stored in laboratory. The chemical compounds of ethyl acetate phase and n-butyl alcohol phase were obtained through the methods of liquid fermentation culture and extraction. The specific compounds were traced and separated by the means of chromatographic separation method such as silica gel column chromatography, reversed-phase Rp-C18 column chromatography and Sephadex LH-20 chromatography combined with thin layer chromatography. The monomeric compounds which obtained by separation and purification were elucidated by means of spectroscopic techniques including mass spectrometry( EI-MS 、 ESI-MS 、HR-ESI-MS)as well as nuclear magnetic resonance(1H-NMR、13C-NMR、H-H COSY、HMBC、HMQC、NOESY). Finally, the activites of some compounds against plant pathogenic fungi were evaluated. The results were as follows:(1)14 compounds were isolated and purified from the crude extract of ethyl acetate phase and n-butyl alcohol phase. According to the spectra and data as well as the references, the compounds were elucidated as chaetomugilin A, chaetomugilin D,chaetomugilin S, chaetomugilin I, chaetomugilin J, chaetomugilin Q, chaetomugilin O,chaetoglobosin A, chaetoglobosin C, ergosterol, ergosterol peroxide, cerevisterol,maltol and anthranilic acid.(2)Antifungal activity of the compounds chaetomugilin A,chaetomugilin D,chaetoglobosin A, chaetoglobosin C, ergosterol, ergosterol peroxide and cerevisterol to the six kinds of plant pathogenic fungi was tested by mycelial growth inhibitory rate method. The results indicated that chaetoglobosin A and chaetoglobosin C have good antifungal activities against Sclerotinia sclerotiorum. The inhibitory effect of chaetoglobosin A is stronger than that chaetoglobosin C. Chaetoglobosin A andchaetoglobosin C have inhibitory activity toward Sclerotinia sclerotiorum with EC50 values of 123.03μg/m L and 213.79μg/m L respectively.In summary, the secondary metabolites and antifungal activities of one strain of Chaetomium sp. were studied, and the chemical compositions of the two compounds with good inhibition activity against plant pathogenic fungi were isolated. This provides a theoretical basis for the development of new biological pesticides, but also provides a theoretical basis for microbial fermentation of such active substances.