Nigella sativa L. seed extract alleviates oxidative stress-induced cellular senescence and dysfunction in melanocytes

Nigella sativa L. seeds have been traditionally used in Chinese folk medicine for centuries to treat vitiligo. This study revealed that the ethanolic extract of Nigella sativa L. (HZC) promotes melanogenesis and alleviates oxidative stress-induced cellular senescence and dysfunction in melanocytes. Consistent with established conventions, the ethanol fraction from Nigella sativa L. seeds was extracted, subsequently concentrated, and lyophilized to assess its herbal effects via MTT assays, tyrosinase activity evaluation, measurement of cellular melanin contents, scratch assays, senescence-associated β-galactosidase (SA-β-gal) staining, ELISA, and Western blot analysis for expression profiling of experimentally relevant proteins. The results showed that HZC significantly increased tyrosinase activity and melanin content while also notably increasing the protein expression levels of Tyr, Mitf, and gp100 in B16F10 cells. In addition, HZC effectively alleviates oxidative stress-induced cellular senescence, improves the condition of melanocytes, and rectifies various functional impairments associated with melanocyte dysfunction. Therefore, our findings suggest that HZC increases melanin synthesis in melanocytes through the activation of the MAPK, PKA, and Wnt signaling pathways, and attenuates oxidative damage induced by H₂O₂ therapy by activating the Nrf2-ACE pathway and enhancing the activity of downstream antioxidant enzymes, thus preventing premature senescence and dysfunction in melanocytes.