New Glycosylated Secondary Metabolites from Marine-Derived Bacteria.

Three new glycosylated secondary metabolites, including a new indole alkaloid, pityriacitrin D ( 1 ), and two new trehalose lipids ( 2 and 3 ), together with three known compounds ( 4 - 6 ) were isolated from two marine-derived bacterial strains, Bacillus siamensis 168CLC-66.1 and Tsukamurella pseudospumae IV19-045. The structures of 1 - 3 were determined by extensive analysis and comparison of their spectroscopic data with literature values. The absolute configurations of sugar moieties were determined by chemical derivatization followed by LC-MS analysis. Cytotoxicity of 1 - 3 against six cancer cell lines was evaluated by SRB assay, and 1 showed moderate activity against all the tested cell lines with GI 50 values ranging from 8.0 to 10.9 µM.