title: Emodin isolated from Polygoni Multiflori Ramulus inhibits melanogenesis through the liver X receptor-mediated pathway.
abstract: Melanogenesis is a physiological process that results in the synthesis of melanin pigments, which play a crucial protective role against skin photocarcinogenesis. We investigated the effects of a Polygoni Multiflori Ramulus extract on melanogenesis and isolated emodin from Polygoni Multiflori as an active compound. In addition, the possible mechanisms of action were examined. We found that emodin inhibited both melanin content and tyrosinase activity concentration and time dependently. Tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 mRNA levels decreased following emodin treatment. However, while the mRNA levels of microphthalmia-associated transcription factor (MITF) were not affected by emodin, emodin reduced MITF protein levels. Furthermore, expression of the liver X-receptor (LXR) α gene, but not the LXR β gene was upregulated by emodin. Moreover, emodin regulated melanogenesis by promoting degradation of the MITF protein by upregulating the LXR α gene. The emodin effects on MITF was found to be mediated by phosphorylation of p42/44 MAPK. Taken together, these findings indicate that the inhibition of melanogenesis by emodin occurs through reduced MITF protein expression, which is mediated by upregulation of the LXR α gene and suggest that emodin may be useful as a hyperpigmentation inhibitor.
authors.affiliation: Department of Genetic Engineering, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon City, 164-19 Gyunggi Do, Republic of Korea.
authors.forename: Mi Ok
authors.initials: MO
authors.lastname: Kim
authors.affiliation: Department of Microbiology, School of Medicine, Kyung Hee University, 024-53 Seoul, Republic of Korea.
authors.forename: Yong Seek
authors.initials: YS
authors.lastname: Park
authors.affiliation: COSMAX R&I Center, COSMAX Inc., Seongnam City, 134-86 Gyunggi Do, Republic of Korea.
authors.forename: Youn Hwa
authors.initials: YH
authors.lastname: Nho
authors.affiliation: COSMAX R&I Center, COSMAX Inc., Seongnam City, 134-86 Gyunggi Do, Republic of Korea.
authors.forename: Seok Kyun
authors.initials: SK
authors.lastname: Yun
authors.affiliation: Biospectrum Life Science Institute, Seongnam City, 132-16 Gyunggi Do, Republic of Korea.
authors.forename: Youngsoo
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Biospectrum Life Science Institute, Seongnam City, 132-16 Gyunggi Do, Republic of Korea.
authors.forename: Eunsun
authors.initials: E
authors.lastname: Jung
authors.affiliation: Department of Food and Nutrition, College of Health Industry, Eulji University, Seongnam City, 131-35 Gyunggi Do, Republic of Korea.
authors.forename: Jean Kyung
authors.initials: JK
authors.lastname: Paik
authors.affiliation: Department of Physical Therapy, College of Health Science, Eulji University, Seongnam City, 131-35 Gyunggi Do, Republic of Korea.
authors.forename: Minhee
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Biomedical Laboratory Science, College of Health Science, Eulji University, Seongnam City, 131-35 Gyunggi Do, Republic of Korea. Electronic address: chiuchun0716@gmail.com.
authors.forename: Il-Hoon
authors.initials: IH
authors.lastname: Cho
authors.affiliation: Department of Genetic Engineering, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon City, 164-19 Gyunggi Do, Republic of Korea. Electronic address: bioneer@skku.edu.
authors.forename: Jongsung
authors.initials: J
authors.lastname: Lee
mesh_terms: D002460:Cell Line; D015536:Down-Regulation / Q000187:drug effects; D004642:Emodin / Q000302:isolation & purification* / Q000494:pharmacology*; D000068676:Fallopia multiflora / Q000737:chemistry*; D006801:Humans; D000071518:Liver X Receptors; D008543:Melanins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008544:Melanocytes / Q000187:drug effects* / Q000378:metabolism; D051739:Microphthalmia-Associated Transcription Factor / Q000235:genetics / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D057093:Orphan Nuclear Receptors / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000071518:Liver X Receptors; D008543:Melanins; D051739:Microphthalmia-Associated Transcription Factor; C000605213:NR1H3 protein, human; D057093:Orphan Nuclear Receptors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D004642:Emodin
keywords: Emodin; Liver X receptor; MITF; Melanogenesis; Polygoni Multiflori Ramulus