Analysis of the antimicrobial activity of propolis and lysozyme in semisolid emulsion systems

Propolis as an active natural substance is attractive due to its antimicrobial and antimycotic properties. Lysozyme was added to semisolid dermatological preparations as a complementary substance capable of potentiating their antimicrobial and antimycotic effect; this substance has been used for several decades as a preservative in food industry. The aim of this study was to model a semisolid emulsion system (o/w) for cutaneous use with moisturizing and antimicrobial properties, where the active substances would be propolis and/or lysozyme. The microbiological examination was performed under aseptic conditions. The microbiological examination was aimed at determining the antimicrobial efficacy of the studied preparation in the solid growth media using the wells technique. The results of the antimicrobial assay showed that the effectiveness of propolis against the growth of S. aureus was intensified by the lysozyme introduced into the emulsion systems. In addition to that, the results of examinations showed that the active substance propolis in emulsion systems more efficiently inhibited spore bacteria (Bacillus cereus) than lysozyme did, yet lysozyme had a more pronounced antimycotic (against Candida albicans) effect, compared to propolis. All studied cream samples inhibited the growth of Gram-negative microorganisms (Escherichia coli). The results of this study suggest that the application of propolis and lysozyme as the active substances may increase the antimycotic and antibacterial effect of the studied preparations.