마우스 세포에서 Pratol의 멜라닌 합성 증진과 항염증 효과

Abstract

Pratol is a 7-hydroxy-4-methoxyflavone found in Trifolium pratense. In this study, we investigated the effects of pratol on melanogenesis and anti-inflammation. We also studied the mechanism of action of pratol in B16F10 melanoma and RAW 264.7 cells. The B16F10 cells and RAW 264.7 cells were treated with various concentrations (6.25, 12.5, 25, and 50 μM) and (25, 50, 100 μM) of pratol respectively to observe its effects. The results in B16F10 cells showed that pratol significantly increased melanin content and tyrosinase activity without being cytotoxic. In addition, pratol strongly increased the expression of tyrosinase and tyrosinase-related protein-1 and 2 by enhancing the expression of microphthalmia-associated transcription factor. Furthermore, pratol stimulated melanogenesis via the phosphorylation of p38, c-Jun N-terminal kinases (JNK), and extracellular signal–regulated kinase (ERK). The findings from an assay searching for the inhibitor revealed that SB203580 (a specific p38 inhibitor) or SP600125 (a p-JNK inhibitor) attenuated pratol-induced cellular tyrosinase activity whereas PD98059 (an ERK inhibitor) did not. Additionally, pratol interfered with the phosphorylation of p-AKT. We also found that pratol-induced melanogenesis was reversed by H89, which is a specific protein kinase A inhibitor. The results in RAW 264.7 cells showed that pratol significantly decreased NO and PGE_2 production without any cytotoxic. In addition, pratol strongly decreased the expression of iNOS and COX-2. Furthermore, pratol reduced proinflammatory cytokines such as tumour necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6. The results suggest that, owing to its multi-functional properties, pratol may be use as potential tanning agent or as therapeutic agent for hair depigmentation, hypopigmentation and inflammation.