Background: Melanin plays a crucial role in camouflage, social communication and
protection against harmful ultraviolet radiations. Melanin is synthesized by melanocytes through
melanogenesis and several intrinsic and extrinsic factors are involved during the process. Any
change occuring in the normal melanogenesis process can cause severe pigmentation problems of
hypopigmentation or hyperpigmentation.
Objective: The present study is based on the evaluation of the effect of thymoquinone on
melanogenesis and their possible mechanism of action using the B16F10 melanoma cell line for the
production via blocking signaling pathways.
Methods: Phase contrast microscopy, cell viability, tyrosinase activity, melanin content and
western blot analysis were used in the present study.
Results: In the present investigation, cultured melanocytes exhibit that the stimulation of melanin
synthesis when treated with thymoquinone. Tyrosinase activity and melanin production in B16F10
melanoma cell line was increased in doze-dependent manner. In western blot, we investigated the
involvement of the cAMP/PKA pathway in thymoquinone induced melanogenesis. It was observed
protein kinase inhibitors PKA, PKC, PKB and MEK1 decreased the stimulatory effects of
thymoquinone from 11.45- fold value to 8.312, 6.631, 4.51, and 7.211-fold value, respectively.
However, the results also prove that thymoquinone may partially induce tyrosinase expression via
PKA, PKB, PKC and MEK1 signaling pathways.
Conclusion: The present finding proposed that thymoquinone is a protective challenger for
melanogenesis and it might be useful for the treatment of hypopigmentary disorders.