Antibacterial Natural Products From Mount Fanjing Cave-derived Fungi

Natural compounds derived from microbial secondary metabolites were an important source for new drug.Fungus from different sources can produce different secondary metabolites with various biological function.Fungus living in cave soil can produce bioactive secondary metabolites with antibiotic activity.Objective: To study fungus from a cave in Mount Fanjing in Guizhou and identify the antibacterial secondary metabolites.Methods: The isolation and purification of compounds were performed by means of column chromatography and HPLC.Their structures were elucidated through the analysis of MS,NMR and specific rotation.The antibacterial activities were assayed by Kirby-Bauer test and the broth dilution method.Results: 48 fungal strains isolated form Mount Fanjing cave,and 2 of them showed antinmicrobial activities.Twenty compounds,helvolic acid(1),gliotoxin(2),bisdethiobis(methylthio)gliotoxin(3),fumiquinazoline A(4),pseurotin A(5),fumitremorgin C(6),verruculogen(7),fumitremorgin B(8),fumiquinazoline C(9),Dibutylphthalate(10),Geumsanol F(11),Geumsanol G(12)?sclerotioramine(13)?glycerol monolinoleate(14),kaempferol(18),Chaetomininel(19),trypacidin(20),1,2-seco-trypacidin(21),monomethylsulochrin(22),(-)-syringaresinol(23)were isolated from the brouth of two fungus RDF13 and RDF 24.Compounds 1 and 2 showed strong antibacterial activities against MRSA,Vibrio parahaemolyticus,Bacillus cereus,Aeromonas hydrophila,Pseudoalteromonas nigrifaciens and Shewanellamarisflavi with minimal inhibitory concentration values from 0.0625 to 2.0 ?g/mL.Compounds 18 showed weak antibacterial activities against Vibrio vulnificus,Edwardsiella tarda and Pseudoalteromonas nigrifaciens.Compounds 18 and 23 were obtained from Aspergillus genus for the first time.Conclusion: The fungus in the cave soil is diverse,which the antibacterial natural products can be found from cave fungus.