Antimelanogenesis effect of Tunisian herb Thymelaea hirsuta extract on B16 murine melanoma cells.
Skin pigmentation is the result of melanogenesis that occurs in melanocytes and/or melanoma cells. Although melanogenesis is necessary for the prevention of DNA damage and cancer caused by UV irradiation, excessive accumulation of melanin can also cause melanoma. Thus, we focused on the antimelanogenesis effect of an extract from Thymelaea hirsuta, a Tunisian herb. Murine melanoma B16 cells were treated with T. hirsuta extract, and then cell viability and synthesized melanin content were measured. We found that the T. hirsuta extract decreased the synthesized melanin content in B16 cells without cytotoxicity. Tyrosinase is a key enzyme of melanogenesis and extracellular signal-regulated kinase (ERK)-1/2 phosphorylation is known to be related to melanogenesis inhibition. To clarify its mechanism, we also determined ERK1/2 phosphorylation and tyrosinase expression level. ERK1/2 was immediately phosphorylated in cells just after treatment with the extract. The tyrosinase expression was inhibited after 24 h of stimulation with the extract. The T. hirsuta extract was fractionated, and we found that one fraction considerably decreased the melanin synthesis in B16 cells and that this fraction contains daphnanes as the main component. This indicates that our findings might be attributable to daphnanes.
Kawano
Mitsuko
M
Alliance for Research on North Africa, University of Tsukuba, Tsukuba, Ibaraki, Japan.
Matsuyama
Kyoko
K
Miyamae
Yusaku
Y
Shinmoto
Hiroshi
H
Kchouk
Mohamed Elyes
ME
Morio
Takahiro
T
Shigemori
Hideyuki
H
Isoda
Hiroko
H
D000818:Animals; D045744:Cell Line, Tumor; D015536:Down-Regulation; D020935:MAP Kinase Signaling System / Q000502:physiology; D008543:Melanins / Q000096:biosynthesis*; D008546:Melanoma, Experimental / Q000188:drug therapy*; D051379:Mice; D014442:Monophenol Monooxygenase / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry / Q000627:therapeutic use*; D029645:Thymelaeaceae / Q000737:chemistry*
D008543:Melanins; D010936:Plant Extracts; D014442:Monophenol Monooxygenase