title: Extracellular melanogenesis inhibitory activity and the structure-activity relationships of ugonins from Helminthostachys zeylanica roots.
abstract: Ugonin J, K, and L, which are luteolin derivatives, were isolated from Helminthostachys zeylanica roots by a series of chromatographic separations of a 50% ethanol/water extract. They were identified using nuclear magnetic resonance (NMR), ultraviolet (UV) spectra, and ultra-performance liquid chromatography coupled to time-of-flight mass spectrometry (UPLC-TOF-MS). In this study, the intra and extracellular melanogenic activity of the ugonins were determined using B16 melanoma cells. The results showed that ugonin J at 12.5, 25, and 50μM reduced extracellular melanin contents to 75, 16, and 14%, respectively, compared to the control. This indicates that ugonin J showed a stronger activity than arbutin, used as the positive control. Moreover, ugonin K showed a more potent inhibition with 19, 8, and 9% extracellular melanin reduction at the same concentrations, than that shown by ugonin J. In contrast, ugonin L did not inhibit intra- or extracellular melanogenic activity. Furthermore, in order to investigate the structure-activity relationships of the ugonins, the intra- and extracellular melanogenic activity of luteolin, methylluteolin, quercetin, eriodictyol, apigenin, and chrysin were determined. Consequently, it was suggested that the catechol and flavone skeleton of ugonin K is essential for the extracellular melanogenic inhibitory activity, and the low polarity substituent groups on the A ring of ugonin K may increase the activity.
authors.affiliation: The United Graduate School of Agricultural Science, Gifu University, 1-1 Yanagido, 501-1193 Gifu, Japan.
authors.forename: Kosei
authors.initials: K
authors.lastname: Yamauchi
authors.affiliation: The United Graduate School of Agricultural Science, Gifu University, 1-1 Yanagido, 501-1193 Gifu, Japan. Electronic address: mitunaga@gifu-u.ac.jp.
authors.forename: Tohru
authors.initials: T
authors.lastname: Mitsunaga
authors.affiliation: Faculty of Applied Biological Science, Gifu University, 1-1 Yanagido, 501-1193 Gifu, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Itakura
authors.affiliation: Department of Chemistry, Faculty of Mathematics and Natural Sciences, Biopharmaca Research Center, Bogor Agricultural University, Jl. Taman Kencana No. 3, Kampus IPB Taman Kencana, Bogor 16151, Indonesia. Electronic address: ime@ipb.ac.id.
authors.forename: Irmanida
authors.initials: I
authors.lastname: Batubara
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor / Q000187:drug effects; D029624:Ferns / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry*; D008543:Melanins / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D008546:Melanoma, Experimental / Q000473:pathology*; D051379:Mice; D015394:Molecular Structure; D018517:Plant Roots / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D005419:Flavonoids; D008543:Melanins; C540912:ugonin K
keywords: B16 melanoma cell; Helminthostachys zeylanica; Tyrosinase; Ugonin J; Ugonin K