Production and purification of a bioactive substance against multi-drug resistant human pathogens from the marine-sponge-derived Salinispora sp.

Objective:To isolate,purify,characterize,elucidate structure and evaluate bioactive compounds from the sponge-derived Salinispora sp.FS-0034.Methods:The symbiotic actinomycete strain FS-0034 with an interesting bioactivity profile was isolated from the Fijian marine sponge Theonella sp.Based on colony morphology and obligatory requirement of seawater for growth,and mycelia morphological characteristics the isolate FS-0034 was identified as a Salinispora sp.The bioactive compound was identified by using various spectral analysis of ultraviolet,high resolution electrospray ionization mass spectroscopy,H nuclear magnetic resonance,correlated spectroscopy and heteronuclear multiple bond coherence spectral data.A minimum inhibitory concentration assay were performed to evaluate the biological properties of the pure compound against multi-drug resistant pathogens.Results:Bioassay guided fractionation of the ethyl acetate extract of the culture of Salinispora sp.FS-0034 by different chromatographic methods yielded the isolation of an antibacterial compound,which was identified as rifamycin W(compound 1).Rifamycin W was reported for its potent antibacterial activity against methicillin-resistant Staphylococcus aureus,wild type Staphylococcus aureus and vancomycin-resistant Enterococcus faecium and displayed minimum inhibitory concentrations of 15.62,7.80 and 250.00 μg/mL,respectively.Conclusions:The present study reported the rifamycin W from sponge-associated Salinispora sp.and it exhibited appreciable antibacterial activity against multi-drug resistant human pathogens which indicated that sponge-associated Actinobacteria are significant sources of bioactive metabolites.

p-Terphenyl alcohols from a marine sponge-derived fungus, Aspergillus candidus OUCMDZ-1051

In order to discover structurally new and bioactive conipounds from marine life,we studied the secondary metabolites of the marine-derived fungi associated with a marine sponge(XS-3)from the Xisha islands.As a result,4-O-methylcandidusin A(1),a new p-terphenyl alcohol,along with nine known analogs(2-10),were isolated and identified from the marine spongederived fungus Aspergillus candidus OUCMDZ-1051.The structures of these compounds were determined by analyzing spectroscopic data,especially ID and 2D NMR.The new compound 1 selectively inhibited the growth of the MDA-MB-46&BT474 and A431 human cancer cell lines with the IC_(50) values of 1.84,6.05 and 0.98 pmol/L,respectively.Compound 1 also displayed a selective antimicrobial activity against Escherichia coli with an MIC value of 27.3 pmol/L.The results indicated 4-O-methylcandidusin A(1)as a potential lead in the new drug discovery for triple negative breast cancer,invasive ductal breast cancer and epidermoid cancer.The antimicrobial metabolites also evidenced a clue for chemical defense of sponges by their associated microorganisms.