Skin-whitening mechanism of cumin (Cuminum cyminum L.) extract.

Skin-whitening effect is closely linked with the melanogenesis inhibitory activity and free radical scavenging capacity. The purpose of the present study was to evaluate the skin-whitening effect of cumin (Cuminum cyminum L.) extract. The whitening activity was evaluated by cell-free mushroom tyrosinase assay, free radical scavenging assay, cell viability assay, cellular tyrosinase assay and melanin content assay using B16F10 murine melanoma cells. The results showed that cumin extract exhibited concentration-dependent inhibitory effect on both monophenolase and diphenolase activities of mushroom tyrosinase (IC₅₀ values of 1.027mg/mL and 0.977mg/mL, respectively). Kinetic study on diphenolase showed that the cumin extract was a reversible mixed-type inhibitor, and the inhibition constant (KI) was determined to be 0.62mg/mL. In addition, cumin extract significantly suppressed melanin production and cellular tyrosinase activity of B16F10 melanoma cells in a concentration and time dependent manner without cytotoxicity. Moreover, cumin extract exerted strong scavenging capacity on DPPH, hydroxyl and superoxide anion radicals. Taken together, these results strongly suggest that cumin is a potential skin-whitening agent for the cosmetic industry.