Lactiplantibacillus plantarum lysate isolated from green tea leaves alleviates the effects of Malassezia restricta on primary human scalp cells

Scalp seborrheic dermatitis (SSD) is characterized by excessive sebum production, flaking, and itching. This condition is associated with an imbalance in the scalp microbiome, particularly the dominance of Malassezia restricta (MR). Antifungal treatments for SSD often fail to address root causes and can lead to side effects, recurrence, and resistant strains with long-term use. This highlights the need for new, more effective solutions to manage the condition. In this study, we investigated whether the lysate of Lactiplantibacillus plantarum APsulloc 331261 (APsulloc), isolated from green tea leaves, and its lipoteichoic acid (LTA), a bacterial cell wall component, have the potential to serve as natural solutions for SSD. The lysate of APsulloc had no direct effect on MR growth or biofilm formation. However, the lysate improved gene expression of tight junctions and inflammatory cytokines, and upregulated differentiation marker proteins in heat-killed MR-treated scalp keratinocytes. On the other hand, heat-killed MR stimulates differentiation signaling in sebocytes and enhances the expression of lipogenesis-related proteins. APsulloc’s lysate alleviated these effects and inhibit lipid production by sebocytes caused by heat-killed MR. LTA from APsulloc was also found to reduce lipogenesis and the secretion of hair loss-related cytokines in human primary sebocytes that were induced by heat-killed MR. Furthermore, both the lysate and LTA protected outer root sheath cell viability against heat-killed MR-induced damage while promoting dermal papilla cell growth. These finding demonstrate the potential of APsulloc’s cell wall components as natural solutions for improving SSD in vitro .