Antiviral and hemolytic activities of surfactin isoforms and their methyl ester derivatives

Inactivation of enveloped viruses (VSV, SFV, and SHV-1) by surfactin lipope ptides was dependent on the hydrophobicity, i.e. the number of carbon atoms of the fatty acid, and on the charge of the peptide moiety as well as on t he virus species. Surfactins with fatty acid chains of 13 carbon atoms show ed very low antiviral activity in comparison to C14 and C15 isoforms. C15 s urfactin monomethyl ester also inactivated SFV which was resistant to the m ixture of surfactin isoforms as produced by Bacillus subtilis. In contrast, the dimethyl ester showed no virus-inactivation capacity. Disintegration o f viral structures as determined by electron microscopy after inactivation of VSV and SFV eras comparable to the titer reduction. The effect of the su rfactin isoforms and methyl esters on erythrocyte hemolysis correlated with the virus-inactivation capacity. Surfactins with a fatty acid chain moiety of 15 carbon atoms and one negative charge showed the highest antiviral ac tivity.