Taxonomic Identification Of Actinomycete Strain H12-15 From South China Sea And Chemical Comstituents From Its Fermented Broth

We investigated species characterization of an antifungal actinomycete strain H12-15,which isolated from sea sediment in South China Sea and optimation of its fermentation,and the chemical constituents of its fermented broth.?1?By investigation on the morphological,physiological and biochemical characteristics,as well as 16 S r DNA gene sequence,strain H12-15 was identified to be Streptomyces antibioticus.It is high homologous in 16 S r DNA sequence with S.antibioticus?accession number NR043348 in Genbank?.?2?We have screened different culture media to secrete more varieties and amount of antifungal components by activity test using agar diffusion method with an indicator?Candida albicans?.So,strain H12-15 was fermentated in a modified Guserium synthetic No.1 medium.?3?We have performed multiple chromatographic approaches including TLC,ODS,silica gel,and Sephadex LH-20 column chromatography,preparative HPLC,etc.,and some spectroscopic methods for the isolation and identification of constituents in the fermented broth.Twenty-three compounds were isolated from ethyl acetate fraction,and identified to be neoantimycin A?1*?,neoantimycin B?2*?,lanosterol?3?,4,4-dimethylzymosterol?4?,ergosta-5,7,22-triene-3?-ol?5?,?-sitosterol?6?,ergosterol peroxide?7?,24-methyl-5?-cholesta-7,22-dien-3?,6?-diol?8?,5?,6?-epoxy-ergosta-8,14,22-triene-3?,7?-diol?9?,5?,6?-epoxy-?22E,24R?-ergosta-8?14?,22-diene-3?,7?-diol?10?,5?,6?-epoxy-?22E,24R?-ergosta-8?14?,22-diene-3?,7?-diol?11?,5?,6?-epoxy-?22E,24R?-ergosta-8?9?,22-diene-3?,7?-diol?12?,?22E,24R?-3?,5?,9?-trihydroxyergosta-7,22-diene-6-one?13?,?22E,24R?-3?,5?,9?,14?-tetrahydroxyergosta-7,22-diene-6-one?14?,ergosta-7,22-diene-3?,5?,6?-triol?15?,ergosta-7,22-diene-3?,5?,6?,9?-tetraol?16?,actinomycin X2?17?,actinomycin D?18?,?2S?-2,3-O-isopropylidene-2,3-dihydroxy-1,1-diindol-3-yl-propane?19#?,antimycin A1a/b?20,21?,antimycin A_2a?22?and antimycin A9?23?.Amonge these compounds,1 and 2 are the first naturally modified natural antimycins with an unusual benzamide unit,and 19 is a new natural product.?4?Antibacterial activity and cytotoxicities for all these compounds were evaluated,antimycins A1a/b?20,21?,A_2a?22?and A9?23?and actinomycins displayed significant antifungal activities and/or cytotoxicities.Among them,neoantimycin A?1?and neoantimycin B?2?showed mild inhibitory activity against human glioblastoma cell line SF-268.