Isolation,Identification And Secondary Metabolites Of Funguses Associated With Four Marine Organisms In Hainan

As an important component of marine life,marine fungi are rich in secondary metabolites and have become an important source of discovering new natural products.Studies show that there are symbiotic relationships between many marine fungi and other marine organisms that allow them to produce more diverse secondary metabolites and possibly even the same or similar active substances as their hosts.Therefore,it is of great research value and potential to fully and effectively explore the natural products of marine symbiotic fungi.In this study,149 strains of fungi were isolated from ten sea grasses,nine sponges and eleven corals and a sanguinolaria chinensis.33 strains were elected by dereplication and their taxonomic status was further determined by ITS sequence analysis,belonging to 3 phyla(Ascomycetes.Rasidiomycetes and Lepidoptera),8 orders and 10 genus.The antibacterial activity test showed that the fermentation products of 12 fungi had strong antibacterial activity against Bacillus subtil is and Staphylococcus aureus.The IPLC was used to screen the fermentation products of these marine-derived fungi.HNMF114 was selected for its diverse secondary metabolites and subjected to large-scale fermentation.The fermentation products were separated and purified by silica gel column,reverse phase ODS column,Sephadex LH-20 gel column chromatography and HPLC,et al.The structure of the compounds was identified by various spectral techniques such as 1H-NMR?13C-NMR?HSQC?HSBC?COSY?MS,et al.26 compounds were identified,8 of which were new compounds,respectively,27-O-deacetyltryptoquivaline(19),5-(l-hydroxyethyl)-2,3-dimethylcy-clopent-2-en-l-one(20),27-O-propionyl-27-O-deacetyltryptoquivaline(21),12-epi-16-dehydroxyl-27-O-deacetyltryptoquival-ine(22),12-epi-16-dehydroxyltrypt-oquivaline(23),12-epi-27-O-deacetyltryptoqu-ivaline(24),tryptoquivaline V(25),tryptoquivaline W(26).18 of which were known compounds,respectively,desmethylkotanin(1),orlandin(2),kotanin(3),(S)-2-Methyl-1-(4-oxo-3,4-dihydr-oquinazolin-2-yl)propyl acetate(4),(S)-2-(l-Hydroxy-2,2-dimethylpropyl)quinazolin-4(3H)-one(5),tryptoquivaline desacetyl derivative(6),fiscalin C(7),27-epi-tryptoquivaline(8),deoxytryptoquivaliiie(9),epi-fiscalin E(10),scequinadoline G(11),tryptoquivaline L(12),quinadolines B(13),neosartoryad-ins B(14),clavatol(15),2,4(1H,3H)-quinazolinedi-one(16),eyclo(L-Trp-L-Trp)(17),lapatin B(18).Finally,the biological activities of some compounds were evaluated by various biological activity assays.The results showed that compounds 3,18 and 24 had the best free radical scavenging rate for DPPH,which were 55.5%,57.8%and 55.5%,respectively,(ascorbic acid,90.87%).Compounds 15 and 26 had better inhibitory effect on acetylcholinesterase,the inhibitory rates were 32.8%and 32.62%,respectively,and(tacrine,85.73%).Compounds 2 and 3 had the best inhibitory effect on alphaglycosidase,the inhibitory rates were 30.22%and 75.31%,respectively,(acarbose,20.97%).