Characterization of novel cyclic lipopeptides produced by Bacillus sp. SY27F

Three new cyclic lipopeptides (compounds 1–3) were isolated from Bacillus sp. SY27F, which collected from the deep-sea hydrothermal vent in the Indian Ocean. The planar structures of compounds 1–3 were characterized by LC–MS, GC–MS and NMR, whereas their absolute configurations were determined by modified Marfey’s analysis and optical rotation contrast. They shared the same heptapeptide chain (N-L-Gln 1 -D-Leu 2 -L-Leu 3 -L-Val 4 -L-Asp 5 -D-Leu 6 -L-Ile 7 -C), differing only by the length of the fatty acid chain. Compounds 1–3 displayed significant cytotoxic activity against DU145, MCF-7 and HepG2 cancer cell lines with IC 50 values of 96.8–190.7 nM and moderate to weak cytotoxicity against A549, HeLa and HT1080, with IC 50 values of 9.3–43.2 μM, respectively. However, none of the three compounds showed any antibacterial activity against Escherichia coli, Staphylococcus aureus and Monilia albicans .