Secondary Metabolites Of Three Strains Of Marine Microbes

Marine resources are of great commercial and medical value in cancer treatment.In this paper,mangroves Streptomyces sp.was taken as the research object to find more novel secondary metabolites with good antitumor activity.Two microorganisms Streptomyces sp.SZ-A15 and Streptomyces sp.SZ-A15 were selected from thirty actinomycetes from Shenzhen,Guangzhou by screening antitumor activity.Streptomyces sp.SZ-A15 was cultured on rice medium by stationary solid method.By column chromatography(including chromatography on silica gel,MCI gel and preparative HPLC)and spectroscopic analyses(including UV?IR?HR-ESI-MS?1D NMR and 2D NMR),sixteen compounds were isolated and identified.Seven of them were new metabolites,characterised as N1-acetyl-N7-o-hydroxy-phenylacetyl cadaverine(1),Ni-acetyl-N7-4"-methyl-3"-pentenoyl cadaverine(2),Ni-acetyl-N7-4"?methyl-pentoyl cadaverine(3),Ni-acetyl-N7-n-hexanoyl cadaverine(4),4-rhamnosyl-phenylethylene(5),2,5-diisobutyl-6-methoxyl-3-rhamnosyl-pyrazine(6),5-(1" 3"-dimethyl-2"-hydroxyl)-2-en-2-methyl-3-rhamnosyl-?-valerolactone(7),respectively.All isolated compounds were evaluated for anti-tumor activity.However,none of them show any cytotoxic activity against non-small cell lung cancer cells H1975.From Streptomyces sp.SZ-A15,two compounds were identified as actinomycin D(17)and actinomycin X2(18)in the culture condition of Gause's synthetic medium.What's more,all isolated compounds were subjected to inhibition of protein BRD4.As for the ability to inhibit protein BRD4,compound 11 exhibited moderate activity with the value of 78.4±2.2%at 10 ?M.Fungus Paecilomyce.s sp.DT-F31 was fermented on YGP liquid culture medium,one compound named viriditin(19)was structurally elucidated.Viriditin did not show expected antifungal activity against Fusarium graminearum.