Studies On Secondary Metabolites And Their Activity From Three Marine Actinomycetes

Marine actinomycete is a kind of gram-positive bacteria, which form the main chemical defense system by their self-bioactive secondary metabolites after millions of years’ evolution. The secondary metabolites usually contain a large number of monomeric compounds with novel structures and good bioactivities which can lay the foundation of the development of the lead compound for marine drugs.Streptomyces sp. SCSIO 5003, SCSIO 1662 and SCSIO ZS0361 were selected by combining with the guiding role of HPLC-DAD-UV spectrum from sixty-four marine actinomycetes. The study was investigated as toamplify fermentation, extraction, isolation, testing the cytotoxic activity and antibacterial activity of the compounds from the secondary metabolites of three Streptomyces sp. SCSIO 5003, SCSIO 1662 and SCSIO ZS0361.The secondary metabolites from the mycelium and broth of Streptomyces sp. SCSIO 5003 were extracted with acetone(1:1, v/v) and butanone(1:1.5, v/v) respectively, and were isolated by using various chromatographic methods as silica gel column chromatography, RP-MPLC and semi-preparative HPLC. Ten compounds such as 5003-A1, 5003-A2, 5003-A3, 5003-A4, 5003-A5, 5003-A6, 5003-A7, 5003-A8, 5003-A9 and 5003-A10 were obtained. On the basis of ESI-HRMS, 1D NMR and 2D NMR analysis, 5003-A2 was identified as Marihysin A. 5003-A3, 5003-A4, 5003-A5 were homologous compounds and all the three were isomerides. 5003-A6, 5003-A7 were both isomerides, certainly which were also two new compounds researched by Sci Finder.The secondary metabolites from the mycelium and broth of Streptomyces sp. SCSIO 1662 were extracted with acetone(1:1, v/v) and butanone(1:1.5, v/v) respectively, and were isolated by using silica gel column chromatography, RP-MPLC and preparative HPLC. Eight compounds as 1662-B, 1662-C, 1662-D, 1662-E, 1662-F, 1662-G, 1662-H and 1662-I were obtained. On the basis of ESI-HRMS, 1D NMR analysis, 1D NMR, 1662-B, 1662-D, 1662-F, 1662-G and 1662-I were identified as Dibutylphthalate, Indole-3-acetic acid, 1H-Indole-3-carbaldehyde, 3-Hydroxyacetylindole and 1H-Indole-3-carboxylic acid, respectively.The secondary metabolites from the mycelium and broth of Streptomyces sp. SCSIO ZS0361 were extracted with acetone(1:1, v/v) and butanone(1:1.5, v/v) respectively, and were isolated by using silica gel column chromatography, RP-MPLC and preparative HPLC. Five compounds as ZS0361-B, ZS0361-C, ZS0361-D, ZS0361-F, ZS0361-G were obtained. On the basis of ESI-HRMS, 1D NMR and 2D NMR analysis, compounds ZS0361-B, ZS0361-D, ZS0361-G were identified as Bafilomycin D, 1H-Indole-3-carbaldehyde and 3-Hydroxy-2-methylpyrone(maltol), respectively. ZS0361-F was a new compound by researching Sci Finder.Minimum inhibitory concentration(MIC) and cytotoxic activity on 23 monomeric compounds were tested by using Broth Dilution Technique and Artemia Biological Lethal Method. The MIC values of compounds 5003-A2, 5003-A3, 5003-A4, 5003-A5, 5003-A6, 5003-A7, 5003-A8 and ZS0361-C were concentration of 128 ?g/m L, which showed inhibition to MRSA. ZS0361-B, ZS0361-C could inhibit MRSE with the MIC values of 64 ?g/m L and 16 ?g/m L. 5003-A8, 1662-I, ZS0361-C were effective to inhibit Bacillus thuringiensis, of which the MIC values were 16 ?g/m L, 32 ?g/m L and 16 ?g/m L, respectively. ZS0361-C was proved to inhibit Enterococcus faecalis ATCC 29212 with the MIC value of 32 ?g/m L. ZS0361-B, ZS0361-C inhibited Micrococcus luteus were also tested, and the MIC values were 64 ?g/m L and 8 ?g/m L. Meanwhile, compounds 5003-A2, 5003-A3, 5003-A4, 5003-A5, 5003-A6, 5003-A7 showed a weak artemia lethal activity, compound ZS0361-F with a moderate artemia lethal activity, while 1662-C with a strong artemia lethal activity, which indicated that the compounds had potential cytotoxic(anti-tumor) activity.