title: Aglycone of Rh4 inhibits melanin synthesis in B16 melanoma cells: possible involvement of the protein kinase A pathway.
abstract: To our knowledge, there is no report that directly shows an inhibitory effect of ginsenoside on melanin synthesis in B16 melanoma cells. Hence, we investigated whether the aglycone of Rh(4) (A-Rh4) inhibits melanin synthesis in B16 melanoma cells, and determined the mechanism of melanin inhibition. We isolated 12 ginsenoside compounds from leaves of Panax ginseng and tested them in B16 melanoma cells. It significantly reduced melanin content and tyrosinase activity under alpha-melanocyte stimulating hormone- and forskolin-stimulated conditions. It significantly reduced the cyclic AMP (cAMP) level in B16 melanoma cells, and this might be responsible for the regulation down of MITF and tyrosinase. Phosphorylation of a downstream molecule, a cAMP response-element binding protein, was significantly decreased according to Western blotting and immunofluorescence assay. These data suggest that A-Rh4 has an anti-melanogenic effect via the protein kinase A pathway.
authors.affiliation: Department of Applied Bioscience, CHA University, Seoul, Korea.
authors.forename: Yun-Mi
authors.initials: YM
authors.lastname: Jeong
authors.forename: Won Keun
authors.initials: WK
authors.lastname: Oh
authors.forename: Tien Lam
authors.initials: TL
authors.lastname: Tran
authors.forename: Wang-Kyun
authors.initials: WK
authors.lastname: Kim
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Sung
authors.forename: Kyeol
authors.initials: K
authors.lastname: Bae
authors.forename: Suman
authors.initials: S
authors.lastname: Lee
authors.forename: Jong-Hyuk
authors.initials: JH
authors.lastname: Sung
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000302:isolation & purification / Q000494:pharmacology*; D045744:Cell Line, Tumor; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D036145:Ginsenosides / Q000302:isolation & purification / Q000494:pharmacology*; D008543:Melanins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D008546:Melanoma, Experimental / Q000378:metabolism; D051379:Mice; D051739:Microphthalmia-Associated Transcription Factor / Q000235:genetics / Q000378:metabolism; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005894:Panax / Q000737:chemistry*; D010766:Phosphorylation / Q000187:drug effects; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D015398:Signal Transduction / Q000187:drug effects*; D000521:alpha-MSH / Q000494:pharmacology
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D017362:Cyclic AMP Response Element-Binding Protein; D036145:Ginsenosides; D008543:Melanins; D051739:Microphthalmia-Associated Transcription Factor; C497235:Mitf protein, mouse; D010936:Plant Extracts; D005576:Colforsin; D000521:alpha-MSH; D000242:Cyclic AMP; D014442:Monophenol Monooxygenase; D017868:Cyclic AMP-Dependent Protein Kinases