Abnormal deposition of melanin may cause an aesthetic skin problem; therefore, the control of unwanted excessive melanin synthesis is the major goal of cosmetic research.
To identify novel tyrosinase (TYR) inhibitors from marine plants and examine their cellular antimelanogenic effects.
The extracts of 50 marine plants endemic to Korea were screened against human TYR. Active constituents were then isolated from the selected plant extracts that showed potential and their chemical structures elucidated. Furthermore, their antimelanogenic effects were examined using murine melanoma B16/F10 cells and human epidermal melanocytes (HEM).
Among the tested extracts, that of Phyllospadix iwatensis Makino exhibited the strongest human TYR inhibitory activity. The active constituents were purified from the butanol fraction of the P. iwatensis extract and identified as hispidulin 7‐sulfate and luteolin 7‐sulfate. Luteolin 7‐sulfate inhibited human TYR more strongly than hispidulin 7‐sulfate, luteolin, hispidulin and arbutin. Furthermore, luteolin 7‐sulfate showed lower cytotoxicity than luteolin in both B16/F10 cells and HEM. Luteolin 7‐sulfate attenuated cellular melanin synthesis more effectively in B16/F10 cells and HEM stimulated by α‐melanocyte‐stimulating hormone and l‐tyrosine than arbutin.
This study demonstrates that luteolin 7‐sulfate isolated from P. iwatensis is a human TYR inhibitor with advantageous antimelanogenic properties, and would be useful for development as a therapeutic agent for the control of unwanted skin pigmentation.
What's already known about this topic?
Previous efforts to develop antimelanogenic agents have investigated the activity of various plants against mushroom tyrosinase. However, this approach is not appropriate because of the inherent differences between mushroom and human tyrosinases.
What does this study add?
This study screened 50 marine plants for human tyrosinase inhibitory effects and found that Phyllospadix iwatensis extract and its constituent, luteolin 7‐sulfate, inhibited human tyrosinase activity and attenuated melanin synthesis in B16/F10 cells and human epidermal melanocytes.
What is the translational message?
Marine plants have attracted attention as under‐researched resources for bioactive compounds, and this study demonstrates that luteolin 7‐sulfate isolated from Phyllospadix iwatensis Makino, a kind of seagrass, is a more potent and safer inhibitor of cellular melanin synthesis than luteolin.
If these findings are confirmed by clinical studies, the flavonoid sulfate may be useful for the control of unwanted skin pigmentation due to excessive melanin synthesis.
Linked Comment: Khotimchenko. Br J Dermatol 2016; 175:457–458.