Antibacterial Effect of Fatty Acid Salts on Oral Bacteria.

Fatty acid salts are a type of surfactant known to have potent antibacterial activity. We therefore examined the antibacterial activities of fatty acid salts against Streptococcus mutans. Potassium caprylate (C10K), potassium laurate (C12K), potassium myristate (C14K), potassium oleate （C18:1K), potassium linoleate (C18:2K), and potassium linolenate (C18:3K), used at a concentration of 175 mM, resulted in a 7 log-unit reduction of S. mutans after a 10-min incubation. The minimum inhibitory concentration (MIC) of C18:2K and C18:3K was 5.5 mM. C12K also demonstrated high antibacterial activity (MIC of 21.9 mM). These results indicate that C12K, C18:2K, and C18:3K have high antibacterial activity against S. mutans, and possess great potential as antibacterial agents.