Adjuvant antibiotic activity of acidic sophorolipids with potential for facilitating wound healing

The sophorolipid class of biosurfactants are finding increasing use in personal care as well as pharmaceutical products and have the potential to disrupt biofilm formation and inhibit growth in a variety of clinically relevant organisms. In order to investigate potential biomedical applications of sophorolipids derived from non-pathogenic organisms, we fractionated and purified glycolipid biosurfactant sophorolipids produced by the yeast Starmerella bombicola, which yielded both acidic C 18-1 acetylated and non-acetylated congeners that were essentially free from other contaminants (>95% purity). These acidic sophorolipids have antimicrobial activities against the nosocomial infective agents Enterococcus faecalis and Pseudomonas aeruginosa with significant reduction in c.f.u.'s at concentrations as low as 5 mgmL-1 In addition, the sophorolipid showed similar effects when combined with kanamycin or cefotaxime against the same two bacterial strains. As a potential use of these sophorolipids is as a component of topically applied creams for treatment of wound infections, it is clear that they must have no demonstrable adverse effect on wound healing. To assess this we evaluated mammalian cell toxicity in vitro using viability tests and revealed no adverse effect on either endothelial or keratinocyte derived cell lines with sophorolipid concentrations