김예지 (숙명여자대학교)

강교빈 (숙명여자대학교)

강교빈 (숙명여자대학교)

김예지 (숙명여자대학교)

이경하 (숙명여자대학교)

The skin microbiome is constantly exposed to cosmetic ingredients and other xenobiotics, which can undergo structural modifications through microbial biotransformation. However, studies on the biotransformation of cosmetic compounds by skin-associated bacteria remain limited. In this study, the microbial metabolism of licochalcone A, a licorice-derived cosmetic ingredient, was investigated using Staphylococcus xylosus. Following xenobiotic treatment of the bacterial culture, the resulting metabolites were annotated based on MS/MS fragmentation similarity, and one metabolite was putatively identified as a hydrogenated derivative (Compound 1). This compound was isolated via preparative liquid chromatography and structurally confirmed by nuclear magnetic resonance (NMR) spectroscopy. Antibacterial activity was evaluated using the Kirby–Bauer disk diffusion method. licochalcone A exhibited the largest inhibitory zone against Aureimonas indicus and the smallest against S. xylosus, whereas the hydrogenated metabolite showed no activity against any of the tested strains at the same concentration. This study provides preliminary insight into the potential for skin bacteria to alter the structure and biological activity of cosmetic xenobiotics through biotransformation.