In vitro cytotoxicity of glucosides isolated from a marine-derived bacterium Bacillus sp. 168CLC-66.1

Abstract

Bacteria are renowned as a promising source of new chemical scaffolds for pharmaceutical research. More than 20% of bacterial natural products are glycosylated derivatives. Several classes of currently used drugs are glycosides such as, macrolides, aminoglycosides, and glycosylated angucyclines. Moreover, cancers are among the top leading causes of death worldwide and there is a continuous demand to find new anti-cancer drugs. During our studies on marine-derived microorganisms, a bacterial strain was isolated from a seaweed sample, Caulerpa sp., collected near Cu Lao Cham peninsula, VietNam, which was identified as Bacillus siamensis 168CLC-66.1 based on 16S rRNA gene sequence analysis. Three glycosides was isolated from the culture broth of the strain, including pityriacitrin D, macrolactin B, and 12′,13′-trans-14′,15′-dihydrobacillaene B. The structures of the isolated compounds were elucidated by spectroscopic methods (MS and NMR) and LC-MS analysis. Their cytotoxic activity was evaluated by SRB assay and pityriacitrin D showed moderate cytotoxicity against all the tested cell lines.