Surfactin isoforms isolated from a mushroom derived Bacillus halotolerans DMG-7-2

A new iso-C-14 [Val(2), Val(7)] surfactin isoform (1) together with eight known ones (2-9), was isolated from the culture of a mushroom derived bacterium, Bacillus halotolerans DMG-7-2. The structures of them were mainly elucidated by NMR and MS data, and the NMR data of 5 also was reported for the first time. The absolute configuration of 1 was determined by Marfey's analysis (for amino acid residues) and the C-13 NMR calculation of the two plausible epimers of 1 (for fatty acid). Compounds 1-9 showed moderate cytotoxicity against two human cancer cell lines (A549, MCF-7) and mice microglial BV2 cells, the IC50 values ranged from 8.91 to 33.00 mu M, and the IC50 values of the positive control 5-FU were 99.94, 71.49 and 0.12 mu M, respectively.

Automated summary

A new isoform of surfactin, along with eight known ones, was isolated from a bacterium derived from mushrooms. These compounds showed moderate cytotoxicity against human cancer cell lines and mice microglial cells, with IC50 values ranging from 8.91 to 33.00 μM. The absolute configuration of the new isoform was determined through analysis and calculation methods.