Assessment of Antimicrobial Activity and Safety of Pediococcus pentosaceus Isolated from Ginseng as a Functional Cosmetic Ingredient

Lactic acid bacteria (LAB) are gaining increasing attention as functional ingredients in the cosmetic industry, particularly those derived from natural plant sources. Although various LAB strains have been widely applied in cosmetic formulations, studies investigating the effects of naturally derived LAB on the skin remain limited. In this study, we isolated an LAB strain from ginseng and evaluated its potential as a functional cosmetic ingredient. The antimicrobial activity of the strain was assessed against skin-associated pathogens <i>Staphylococcus aureus</i> and <i>Staphylococcus epidermidis</i>, while cytotoxicity was evaluated using HaCaT and Caco-2 cells. Considering the limitations of vertebrate animal testing, infection and survival assays were conducted using <i>Galleria mellonella</i> larvae as an alternative in vivo model. The ginseng-derived strain exhibited 99.93% similarity to <i>Pediococcus pentosaceus</i> and was designated <i>P. pentosaceus</i> THG-219. It exhibited an MIC of 0.625 mg/mL and 1.25 mg/mL against <i>S. aureus</i> KCTC 3881 and <i>S. epidermidis</i> KCTC 1917, respectively. Its antimicrobial activity was further enhanced following ethyl acetate fractionation. <i>P. pentosaceus</i> THG-219 showed no toxicity in <i>G. mellonella</i> larvae and exerted antibacterial effects in this model. No cytotoxicity was observed in HaCaT and Caco-2 cells. Furthermore, <i>P. pentosaceus</i> THG-219 promoted host cell adhesion while inhibiting pathogen adhesion. It also exhibited excellent acid, bile, and heat tolerance, suggesting strong survivability under harsh conditions. Collectively, these results indicate that <i>P. pentosaceus</i> THG-219, isolated from ginseng, is a promising, safe, and stable candidate for development as a functional cosmetic ingredient.