The Diatom Odontella aurita Modulates Melanogenesis in B16-F0 Cell Line

Melanin, a pigment synthesized by melanocytes, serves as the primary defense against UV-induced skin damage due to its potent antioxidant properties. There is increasing interest in natural substances capable of modulating the melanogenic pathway, particularly in hypopigmentation disorders. This study investigated the effect of methanolic extracts from the diatom Odontella aurita—authorized as a food supplement in the EU—on melanogenesis in the B16-F0 murine melanoma cell line. The research evaluated melanin content, tyrosinase activity, and the expression of melanogenesis-related genes and proteins at defined time points. Metabolomic and biochemical analyses were performed to characterize the extract’s composition. Treatment with O. aurita extract significantly increased melanin content in B16-F0 cells by 45% (p < 0.01) compared to control. Tyrosinase activity was elevated by 38% after 24 h (p < 0.01), with gene and protein expression analyses confirming upregulation of Tyrosinase (TYR) after 0.5 h, Tyrosinase Related Protein-1 (TRP1) after 1 h, and Tyrosinase Related Protein-2 (TRP2) after 8 h. The extract also enhanced the cellular antioxidant environment, as evidenced by increased levels of metabolic cofactors and pigment-precursor amino acids. O. aurita methanolic extract accelerates and sustains melanin synthesis and tyrosinase activity, distinguishing its effect from single-compound inducers. These findings support the therapeutic potential of O. aurita for pigmentary disorders and skin health. Further studies should investigate its efficacy and safety in vivo and explore its application in cosmeceutical and nutraceutical formulations.