Nano-sized lysate of Lactiplantibacillus plantarum isolated from green tea leaves as a potential skin care ingredient

Fermentation products and lysates of lactic acid bacteria (LAB) have been developed as cosmetic ingredients. The topical application of certain LAB strains can improve skin health and combat skin diseases. Here, we investigated the effects of nano-sized lysate of Lactiplantibacillus plantarum APsulloc 331261 (NLAP) isolated from green tea leaves on human skin cells and a reconstructed human epidermis (RHE) model. NLAP increased the expression of genes involved in skin barrier functions such as proliferation, differentiation, tight junction formation, and antimicrobial peptides in normal human epidermal keratinocytes. NLAP prevented the decrease in the expression of differentiation markers and increased release of inflammatory cytokines in keratinocytes cultured with Staphylococcus aureus. NLAP-induced improvements in gene expression and cytokine levels were also observed in RHE treated with heat-killed S. aureus. Additionally, the skin barrier-strengthening effect of NLAP was confirmed by comparing the penetration of the fluorescent dye into the RHE. These findings suggest that NLAP could aid skin barrier function, protect the skin against detrimental bacteria, and suppress inflammatory responses; thus, it can be developed as a skincare ingredient.