SNA077, an Extract of Marine Streptomyces sp., Inhibits Melanogenesis by Downregulating Melanogenic Proteins via Inactivation of cAMP/PKA/CREB Signaling

Excess melanin in skin is known to be the main cause of hyper-pigmentary skin diseases such as freckles and lentigo. This study aimed to evaluate the depigmenting efficacy of an extract from the marine microorganism strain, Streptomyces sp. SNA077. To determine the anti-melanogenic efficacy of SNA077, we assessed the melanin contents of SNA077-treated B16, Melan-a, and MNT-1 cells. We observed the expression of key enzymes in melanogenesis via qRT-PCR and Western blot analyses. We further estimated the skin-whitening effect of SNA077 using a skin-equivalent model. SNA077 dramatically decreased the melanin production of B16 cells, Melan-a, and MNT-1 cells. In B16 cells treated with SNA077, the activity of cellular tyrosinase was clearly inhibited. In addition, the mRNA and protein expression levels of melanogenic genes were suppressed by SNA077 treatment in B16 and MNT-1 cells. Upstream of tyrosinase, the expression levels of phospho-CREB, phospho-p38, PKA activity, cyclic AMP production, and MC1R gene expression were inhibited by SNA077. Finally, SNA077 clearly showed a skin-brightening effect with a reduced melanin content in the skin tissue model. Collectively, our results suggest for the first time that an extract of marine Streptomyces sp. SNA077 could be a novel anti-melanogenic material for skin whitening.