Studies On The Secondary Metabolites Of Three Marine-derived Fungi

Marine-derived microorganisms can produce novel bioactive secondary metabolitesthrough their unique metabolic pathways, and have become the great importantresource for natural products research. This paper describes the systematic study onchemical structure of three marine-derived fungal secondary metabolites, andpreliminary evaluation of theirs biological activities.A total of150strains was isolated and purified from eighteen marine samples,including eight mangrove mud samples collected in Maoming and Zhanjiang,Guangdong, as well as ten marine mud samples collected in the norther South ChinaSea. Thirteen bioactive strains were obtained through the routine laboratory screeningmodel. Two fungi with cytotoxic activities against P388and abundant series productswas chosen as the fermented strains among them, as well as one spone-associatedfungus Epicoccum sp. JJY-40.Their fermentation was performed under the optimal conditions, and then thefermented products were isolated using conventional column chromatography andsemi-preparative high performance liquid chromatography method. As a result, threecompounds were isolated from the extract of sponge-associated fungus Epicoccum sp.JJY-40, eleven compounds were isolated from the extract of fungus Penicillinchrysogenum PJX-17, and twenty compounds were isolated from the extract of fungusPenicillin chrysogenum PJX-15. In short, thirty-four compounds were got.Basing on various spectrum analysis methods, the structures of twenty-twocompounds (1-22) were determined. The structural types of the twenty-twocompounds include: two C-galactopyranosy pyrones conjugated heptaene (1-2),eleven polyketides (3-4,14-22), three benzene derivatives (5-7), three citrinincompounds (8-10), one steroid alcohols (11), one nucleoside (12), onesesquiterpene(13). Among them, four compounds are new, including oneC-galactopyranosy pyrones (1) and three sorbicillin dimeric derivatives（3-4，14）.In transient transfection and NF-κB-dependent reporter gene expression assay,compounds1and2showed weak NF-κB inhibitory activities in mouse macrophage(RAW264.7). The anti-influenza A virus (H1N1) activities of compounds1and2 were also evaluated by the cytopathic effect (CPE) inhibition assay in MDCK cells,they showed significant inhibitory effects. New compounds3-4were evaluated fortheir anti-tumor activity against P-388, K562and HL60cells by the MTT or SRBmethods, and they showed weak cytotoxicities. Other biological activities are beingevaluated.To sum up,150strains were isolated from marine-derived mud samples, thirteenfungi of cytotoxic activities were obtained by integrated screening.22compoundswere isolated from the extracts of three fungi, including one rare C-galactopyranosypyrone, and three new sorbicillin dimmer derivatives. These research results providenew marine-derived fungi; add new structure types to natural product research; at thesame time also provide one new chemical structure for antivirus andanti-inflammatory activity research.