Isolation?Structure Elucidation And Biological Assay Of The Secondary Metabolites From Streptomyces Spectabilis

Bioassay-guided studies on the anti-bacterial substances in the culture of Streptomyces spectabilis LXR1H-8 were performed.Through extraction and successive chromatography,two active compounds were obtained from the culture of Streptomyces spectabilis LXR1H-8.The two compounds were identified to be streptovaricin D?StrD?and streptovaricin A?StrA?on the basis of spectroscopic analyses,including1D-and 2D-NMR,MS,and UV.The anti-bacterial and cytotoxic activities of the two compounds were evaluated.The results showed that the MIC of StrD and StrA against Sarcina lutea was 0.78 and 0.39?g/mL in vitro.The phenol coefficient of StrA and StrD was 8000 and 4000,respectively.The MIC of StrD and StrA against MRSA was 12.5 and 3.12?g/mL,respectively.StrA displayed cytotoxicity against HCT-116 cell line and A-549 cell line with the IC₅₀0 values of 0.22 and 0.23?M,While StrD didn't show obvious cytotoxicity.