Bioactive Secondary Metabolites From Four Marine-Derived Actinomycetes

Staurosporines and anthracyclines as well as their analogues are compounds of potential values towards the research and development of medicine due to strong cytotoxic activity.Based on cytotoxic activities of crude extracts,we selected 4 strains to study:Streptomyces sp.ZS-A19 and Streptomyces sp.ZS-A26 with staurosporines as main products,while Streptomyces sp.ZS-A36 and Streptomyces sp.NB-A1 3 with anthracyclines as main products.Silica gel column chromatography,Sephadex LH-20 chromatography and high performance liquid chromatography were used to separate and purify their crude extracts.The compounds were identified by 1D NMR,2D NMR,MS,UV and IR spectroscopy.37 compounds in total were isolated and identified from fermentation extracts of four strains,including six new compounds andicoquinone A(27),andicoquinone B(28),andicoquinone C(29),andicoquinone D(30),(1’S,2’R,3’R,4’R,5’R)-decilorone B(31),(1’R)1,8-dihydroxy-2-(1-hydroxyethyl)-3-methylanthraquinone(33)and a new natural product 2-hydroxy-xanthorrhoeol(19).Some compounds were evaluated in terms of tumor cell proliferation inhibitory activities and antibacterial activity.Staurosporines compounds exhibited cytotoxic activity against PC3 cells with IC50 values ranging from 0.04 μM to 16.2 μM.Compounds 28～33 exhibited cytotoxic activity against PC3 cells with IC50 values of 0.92 μM,>10 μM,7.0 μM,2.1 μM,2.2 μM,9.8 μM,respectively.Besides,compound 31 exhibited potent cytotoxic activity against SW620 cells with the IC50 value of 2.5μM.