Abstract
This study focused on the antifungal and fungicidal effects of potassium 2-butyloctanoate (isoC12K), a branched fatty acid salt, against Malassezia furfur. Antifungal susceptibility tests showed that isoC12K exhibited high antifungal activity, with minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) at a low concentration of 0.156 wt/v%. Furthermore, the FDA–PI double fluorescence staining method suggested that isoC12K may act fungicidally by impairing the cell membrane function of M. furfur. Furthermore, when isoC12K was used in combination with a commercially available shampoo, it was found that the addition of isoC12K conferred antifungal activity to the products that did not exhibit antifungal activity when used alone. In addition, a model shampoo containing isoC12K as a cleansing ingredient was prepared, and its cleansing effect and effect on hair were evaluated. The results showed that it had the same cleansing ability as a shampoo containing the conventional surfactant SDS, while tending to cause less damage to the hair surface and internal proteins. These results demonstrate that isoC12K possesses high antifungal activity against M. furfur while also combining functionality as a cleansing agent with low damage to hair.
