Anti-Aging, Anti-Inflammatory, and Cytoprotective Properties of Lactobacillus- and Kombucha-Fermented C. pepo L. Peel and Pulp Extracts with Prototype Skin Toner Development

This study examined the cosmetic potential of extracts from the peel and pulp of fermented pumpkin (Cucurbita pepo L.). Fermentation was carried out using Lactobacillus strains (L. plantarum, L. rhamnosus, L. fermentum, and L. paracasei) and kombucha (SCOBY). Fermentation was carried out for 3 days (for lactic acid bacteria) and 10 and 20 days (for kombucha). The obtained products were analyzed by LC-MS for phytochemical composition and assessed for their antioxidant capacity (DPPH and ABTS assays) and ROS reduction in keratinocytes (HaCaT) and fibroblasts (HDF). The obtained ferments demonstrated cytoprotective effects (using Alamar Blue and Neutral Red assays). Both kombucha ferments and certain strains of Lactobacillus ferments demonstrated anti-aging effects (by inhibiting collagenase, elastase, and hyaluronidase) and anti-inflammatory effects (by significantly affecting IL-6 and IL-1β cytokine levels). A moisturizing skin toner containing the extracts and ferments was developed and tested for cytoprotective effects on HaCaT keratinocytes. The results confirm that fermented pumpkin peel and pulp extracts can be used as multifunctional cosmetic ingredients with the potential to provide antioxidant protection, anti-aging, and skin regeneration.