title: Inhibitory effect of Cinnamomum osmophloeum Kanehira ethanol extracts on melanin synthesis via repression of tyrosinase expression.
abstract: Melanin contributes to skin color, and tyrosinase is the enzyme that catalyzes the initial steps of melanin formation. Therefore, tyrosinase inhibitors may contribute to the control of skin hyperpigmentation. The inhibition of tyrosinase activity by Cinnamomum zeylanicum extracts was previously reported. In this report, we test the hypothesis that Cinnamomum osmophloeum Kanehira, an endemic plant to Taiwan, contains compounds that inhibit tyrosinase activity, similar to C. zeylanicum. The cytotoxicity of three sources of C. osmophloeum Kanehira ethanol extracts was measured in B16-F10 cells using a methyl thiazolyl tetrazolium bromide (MTT) assay. At concentrations greater than 21.25 μg/mL, the ethanol extracts were toxic to the cells; therefore, 21.25 μg/mL was selected to test the tyrosinase activities. At this concentration, all three ethanol extracts decreased the melanin content by 50% in IBMX-induced B16-F10 cells. In addition to the melanin content, greater than 20% of the tyrosinase activity was inhibited by these ethanol extracts. The RT-PCR results showed that tyrosinase and transcription factor MITF mRNAs expression were down-regulated. Consistent with the mRNA results, greater than 40% of the human tyrosinase promoter activity was inhibited based on the reporter assay. Furthermore, our results demonstrate that the ethanol extracts protect cells from UV exposure. C. osmophloeum Kanehira neutralized the IBMX-induced increase in melanin content in B16-F10 cells by inhibiting tyrosinase gene expression at the level of transcription. Moreover, the ethanol extracts also partially inhibited UV-induced cell damage and prevented cell death. Taken together, we conclude that C. osmophloeum Kanehira is a potential skin-whitening and protective agent.
authors.affiliation: Department of BioIndustry Technology, Da-Yeh University, Changhua 51591, Taiwan.
authors.forename: Shih-Chieh
authors.initials: SC
authors.lastname: Lee
authors.affiliation: Department of BioIndustry Technology, Da-Yeh University, Changhua 51591, Taiwan.
authors.forename: Chun-Hao
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Department of Molecular Biotechnology, Da-Yeh University, No. 168, University Rd., Dacun, Changhua 51591, Taiwan.
authors.forename: Chih-Wen
authors.initials: CW
authors.lastname: Yu
authors.affiliation: Department of Molecular Biotechnology, Da-Yeh University, No. 168, University Rd., Dacun, Changhua 51591, Taiwan; Department of Bioresources, Da-Yeh University, Changhua 51591, Taiwan.
authors.forename: Hsiao Ling
authors.initials: HL
authors.lastname: Chen
authors.affiliation: Department of Molecular Biotechnology, Da-Yeh University, No. 168, University Rd., Dacun, Changhua 51591, Taiwan.
authors.forename: Wei-Tung
authors.initials: WT
authors.lastname: Huang
authors.affiliation: Department of Molecular Biotechnology, Da-Yeh University, No. 168, University Rd., Dacun, Changhua 51591, Taiwan.
authors.forename: Yun-Shiang
authors.initials: YS
authors.lastname: Chang
authors.affiliation: Department of BioIndustry Technology, Da-Yeh University, Changhua 51591, Taiwan.
authors.forename: Shu-Hsien
authors.initials: SH
authors.lastname: Hung
authors.affiliation: Department of Molecular Biotechnology, Da-Yeh University, No. 168, University Rd., Dacun, Changhua 51591, Taiwan. Electronic address: tailin@mail.dyu.edu.tw.
authors.forename: Tai-Lin
authors.initials: TL
authors.lastname: Lee
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D027424:Cinnamomum / Q000737:chemistry*; D015536:Down-Regulation / Q000187:drug effects; D000431:Ethanol / Q000737:chemistry*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D008543:Melanins / Q000096:biosynthesis*; D008546:Melanoma, Experimental / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D051379:Mice; D051739:Microphthalmia-Associated Transcription Factor / Q000235:genetics; D014442:Monophenol Monooxygenase / Q000172:deficiency* / Q000235:genetics*; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology* / Q000633:toxicity; D011401:Promoter Regions, Genetic / Q000235:genetics; D020011:Protective Agents / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D062327:Skin Lightening Preparations / Q000494:pharmacology; D013624:Taiwan; D014158:Transcription, Genetic / Q000187:drug effects; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D008543:Melanins; D051739:Microphthalmia-Associated Transcription Factor; D010936:Plant Extracts; D020011:Protective Agents; D012333:RNA, Messenger; D062327:Skin Lightening Preparations; D000431:Ethanol; D014442:Monophenol Monooxygenase
keywords: B16-F10 melanoma cells; Cinnamomum osmophloeum Kanehira ethanol extract; MITF; Skin whitening; Tyrosinase; Tyrosinase promoter activity