Malignant melanoma is responsible for 3.0 and 1.7% of cases of tumor incidence and tumor-associated mortality, respectively, in the Caucasian population. Melanoma is a type of skin cancer that occurs when melanocytes mutate and divide uncontrollably. Nypa fruticans Wurmb (NF) is abundant in phytochemicals (polyphenols and flavonoids) and is traditionally used to treat diseases of the respiratory tract. The present study investigated the inhibitory effect of the ethyl acetate fraction of NF (ENF) on melanogenesis-related factors in isobutylmethylxanthine-treated B16F10 melanoma cells. Phenolics and flavonoids (caffeic acid, catechin, epicatechin and hirsutine) in ENF were analyzed via liquid chromatography-mass spectrometry. In addition, the main factors involved in melanogenesis were identified using immunoblotting, reverse transcription-polymerase chain reaction (RT-PCR), RT-quantitative PCR and immunofluorescence. ENF significantly suppressed the expression of tyrosinase (TYR) and TYR-related proteins 1 and 2 (TYRP-1/2), which are the main factors involved in melanogenesis. ENF also inhibited the expression of microphthalmia-associated transcription factor (MITF) by phosphorylating the related cell signaling proteins (protein kinase B, mammalian target of rapamycin, phosphoinositide 3-kinase and cAMP response element-binding protein). Furthermore, ENF inhibited the phosphorylation of extracellular signal-regulated kinase and thereby downregulated melanogenesis. In conclusion, ENF inhibited melanogenesis by suppressing MITF, which controls TYRP-1/2 and TYR. These results suggested that ENF may be a natural resource that can inhibit excessive melanin expression by regulating various melanogenesis pathways.
Abeliophyllum distichum (A. distichum, Korean endemic plant) is one genus and one species in the Oleaceae family. According to the color variation of petals and calyx, A. distichum is classified as A. distichum (white flower), A. distichum for. lilacinum (pink flowers), A. distichum for. eburneum (ivory flowers), and Okhwang 1 (golden flowers). In previous studies, bioactivities (antioxidant, anti-inflammatory, and anti-cancer) of A. distichum have been reported. We conducted a comparison of the differences in bioactive compounds and the anti-inflammatory effects on macrophages among four flowers of A. distichum (FAD). The identification and quantification of glycosides were analyzed by HPLC/PDA and LCMS. These results were shown FAD has rutin, hirsutrin, and acteoside. Antioxidant activity of FAD significantly decreased reactive oxygen species. In addition, FAD reduced the expression of pro-inflammatory mediators (nitric oxide, iNOS, and COX-2) in lipopolysaccharide-induced RAW 264.7 cells. For further study, we investigated the regulation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. In conclusion, FAD may exert anti-inflammatory effects by suppressing inflammatory mediators via regulations of NF-κB and MAPK signaling pathways. Therefore, these findings suggest that FAD is a potential resource as a preventative or therapeutic agent for inflammation.
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