Antimelanogenic and Antioxidant Effects of Postbioics of <i>Lactobacillus</i> Strains in α-MSH-Induced B16F10 Melanoma Cells via CREB/MITF and MAPKs Signaling Pathway

Abnormal melanin synthesis can lead to severe skin problems. This study investigated the anti-melanogenic effects on α-melanocyte stimulating hormone (α-MSH)-induced B16F10 cells using cell-free supernatants of <i>Lactiplantibacillus plantarum</i> WB326 and <i>Levilactobacillus brevis</i> WB2810. Samples were prepared using 1 mg/ml freeze-dried culture supernatant. Cell viability was assessed using B16F10 cells and MTT assay. Tyrosinase inhibition and melanin content decreased in the samples compared to those treated with α-MSH. This effect was also observed when L-DOPA staining was used under a microscope. Moreover, the mRNA expression levels of microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 decreased in the sample-treated group. Protein expression of the CREB/MITF/MAPK signaling pathway was also reduced. Using HPLC analysis, lactic and acetic acids were detected in the culture supernatants. Finally, the antioxidant effects of the samples were confirmed by comparison with those of Trolox and arbutin. According to the experimental results, their utilization is possible in the fields of functional materials and cosmetic ingredients.