title: Inhibition of melanogenesis by Xanthium strumarium L.
abstract: Xanthium strumarium L. (Asteraceae) is traditionally used in Korea to treat skin diseases. In this study, we investigated the effects of a X. strumarium stem extract on melanin synthesis. It inhibited melanin synthesis in a concentration-dependent manner, but it did not directly inhibit tyrosinase, the rate-limiting melanogenic enzyme, and instead downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase expression. MITF, the master regulator of pigmentation, is a target of the Wnt signaling pathway, which includes glycogen synthase kinase 3β (GSK3β) and β-catenin. Hence, the influence of X. strumarium stem extract on GSK3β and β-catenin was further investigated. X. strumarium induced GSK3β phosphorylation (inactivation), but the level of β-catenin did not change. Moreover, a specific GSK3β inhibitor restored X. strumarium-induced melanin reduction. Hence, we suggest that X. strumarium inhibits melanin synthesis through downregulation of tyrosinase via GSK3β phosphorylation.
authors.affiliation: Department of Biochemistry, Chung-Ang University College of Medicine, Seoul, Republic of Korea.
authors.forename: Hailan
authors.initials: H
authors.lastname: Li
authors.forename: Young Sil
authors.initials: YS
authors.lastname: Min
authors.forename: Kyoung-Chan
authors.initials: KC
authors.lastname: Park
authors.forename: Dong-Seok
authors.initials: DS
authors.lastname: Kim
mesh_terms: D000818:Animals; D002461:Cell Line, Transformed; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D008543:Melanins / Q000235:genetics / Q000378:metabolism; D008544:Melanocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D051739:Microphthalmia-Associated Transcription Factor / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D010858:Pigmentation / Q000235:genetics; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D018547:Plant Stems / Q000737:chemistry; D060449:Wnt Signaling Pathway / Q000187:drug effects / Q000235:genetics; D031210:Xanthium / Q000737:chemistry*; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism
chemical_list: C495267:CTNNB1 protein, mouse; D008543:Melanins; D051739:Microphthalmia-Associated Transcription Factor; C497235:Mitf protein, mouse; D010936:Plant Extracts; D051176:beta Catenin; D014442:Monophenol Monooxygenase; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D038362:Glycogen Synthase Kinase 3