Antimicrobial Activity of Phytosphingosine Nanoemulsions against Bacteria and Yeasts

Abstract

Phytosphingosine (PS) is a natural antimicrobial ingredient present in the mammalian stratum corneum ofthe skin. The skin surface is the first line defense system against microbial colonization and infections. Theaim of this study was to investigate in vitro antimicrobial effects of PS and PS-hydrochloride (PSHCl)nanoemulsion (NE) formulations and solutions against bacteria and fungi. Minimum inhibitoryconcentrations (MICs) of the PS-NE and PSHCl-NE formulations and PS/PSHCl solutions were determinedby microdilution method against Gram-positive/Gram-negative bacteria and yeasts. Inhibitory effects werealso examined by disc diffusion method and inhibition zone diameters were determined. PS/PSHCl solutionsand PS-NE/PSHCl-NE formulations were prepared in different conditions. Physicochemical properties of theNEs were characterized and antimicrobial activities were evaluated. In this study we reported that the PS andPSHCl and NEs had variable antimicrobial activities for a variety of Gram-positive bacteria (MIC range 1μg/ml to 1024 μg/ml), Gram-negative bacteria (MIC range 8 μg/ml to 1024 μg/ml) and Candida strains (MICrange 8 μg/ml to 512 μg/ml). Sphingolipids are part of the natural defense system of the body. Wedemonstrated that PS and PSHCl solutions and NEs have broad antimicrobial activity against bacteria andyeasts. In addition, the newly developed formulations may have potential for prophylactic and therapeuticintervention in infections.