title: Inhibitory effect of ephedrannins A and B from roots of Ephedra sinica STAPF on melanogenesis.
abstract: BACKGROUND
  Melanogenesis, a process producing the pigment melanin in human skin, eyes and hair, is a major physiological response against various environmental stresses, in particular exposure to ultraviolet radiation, and its pathway is regulated by a key enzyme, tyrosinase. In this study, we evaluated the effects of ephedrannins A and B, which are polyphenols from the roots of Ephedra sinica, commonly used in herbalism in oriental countries, on mushroom tyrosinase and melanogenesis in B16F10 melanoma cells.
  
  
  METHODS
  Their effects on mushroom tyrosinase were determined via kinetic studies using a spectrophotometric analysis and those on melanin and tyrosinase production in melanoma cells treated with α-MSH (melanin stimulating hormone) were examined using PCR and ELISA.
  
  
  RESULTS
  Both ephedrannins A and B exhibited concentration-dependent inhibitory effects on L-tyrosine oxidation by mushroom tyrosinase, and the inhibition mechanism was competitive and reversible with L-tyrosine as the substrate. In addition, melanin production in melanoma cells was also suppressed in a concentration-dependent manner by ephedrannins A and B without significant effects on cell proliferation at the concentrations tested. Both compounds showed inhibitory effects on melanin production by suppressing the transcription of tyrosinase in the cells.
  
  
  CONCLUSIONS
  Both compounds exhibited significant inhibitory effects, but the inhibition by ephedrannin B was much more effective than that by ephedrannin A. Both ephedrannins A and B may be good candidates for a whitening agent for skin.
  
  
  CONCLUSIONS
  This is the first report that describes effective inhibition of melanin production by ephedrannins A and B isolated from Ephedra roots.
authors: Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon 200-701, Republic of Korea.
authors: Ik-Soo
authors: IS
authors: Kim
authors: Cell Therapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Republic of Korea.
authors: Sung-Jin
authors: SJ
authors: Yoon
authors: Cell Therapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Republic of Korea.
authors: Young-Jun
authors: YJ
authors: Park
authors: Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon 200-701, Republic of Korea. Electronic address: leehbong@kangwon.ac.kr.
authors: Hee-Bong
authors: HB
authors: Lee
mesh_terms: D000818:Animals; D055162:Biocatalysis / Q000187:drug effects; D015153:Blotting, Western; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D029790:Ephedra sinica / Q000737:chemistry*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects; D007700:Kinetics; D008543:Melanins / Q000096:biosynthesis*; D051379:Mice; D015394:Molecular Structure; D014442:Monophenol Monooxygenase / Q000235:genetics / Q000378:metabolism*; D010936:Plant Extracts / Q000494:pharmacology; D018517:Plant Roots / Q000737:chemistry*; D044945:Proanthocyanidins / Q000737:chemistry / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013379:Substrate Specificity; D014443:Tyrosine / Q000378:metabolism
chemical_list: D008543:Melanins; D010936:Plant Extracts; D044945:Proanthocyanidins; C556561:ephedrannin A; C539087:ephedrannin B; D014443:Tyrosine; D014442:Monophenol Monooxygenase
keywords: Anti-melanogenesis; Competitive inhibition; Epehdra sinica; Ephedrannin A; Ephedrannin B; Tyrosinase activity