Secondary Metabolites Of Two Marine Shrimp Gut Fungi Aspereillus Sp.

Gut Symbiotic Fungi of Marine animal,a major group of special microorganisms,can produce novel bioactive compounds and is an important source of new bioactive natural products.In order to get new lead compounds with novel structures and potent bioactivities,two strains of gut symbiotic fungi DX5H and DX4H,isolated from marine shrimp,were chosen to investigate the secondary metabolites.16 compounds were seperated and purified by making full use of silica gel thin layer chromatography,silica gel column chromatography,Sephadex LH-20 column chromatography,ODS column chromatography,HPLC and so on.DX4H(Aspergillus sp.),which was isolated from the gut of marine shrimp collected from theseaside of Zhoushan,Zhejiang Province,was cultured in the 2#medium and 7 compounds including one ergosterol compound(compound 5),one diphenyl ether compound(compound 6),one cyclic peptide compound(compound 7),and four indole diketopiperazine(1-4)were isolated and identified.Compounds 1-4 contained the same planar structure and 1-3 were novel stereoisomers of WIN 64821(4).Three new compounds were identified by the mass and NMR spectra,CD spectrum,and Marfey method.The cytotoxicity and antimicrobial activity of novel compounds were tested through MTT method andpaper disc method,respectively.Unfortunately,the tested compounds showed no obvious antibacterial activity and cytotoxicity.The strain DX5H(Aspergillus fumigatus)was incubated with 2#medium and extracted to obtain the extract.The compounds 8-16,were isolated and purified,and identified by various modern spectral techniques(NMR,MS,UV,IR),which included one ergosterol(compound 8),an ergenol(compound 9),an epoxy compound(compound 10),one monomethylsulochrin(compound 11),three indole diketopiperone alkaloid compounds(compounds 12-14),and two quinazolinone alkaloid compounds(compounds 15-16).