title: Usefulness of alkaline hydrogen peroxide oxidation to analyze eumelanin and pheomelanin in various tissue samples: application to chemical analysis of human hair melanins.
abstract: Eumelanin and pheomelanin in tissue samples can be specifically measured as the markers pyrrole-2,3,5-tricarboxylic acid (PTCA) and 4-amino-3-hydroxyphenylalanine after acidic permanganate oxidation and hydroiodic acid hydrolysis, respectively. Those degradation methods, although widely applied, are not easily performed in most laboratories. To overcome this difficulty, we developed alkaline H(2)O(2) oxidation in 1 M K(2)CO(3) that produces, in addition to the eumelanin marker PTCA, thiazole-2,4,5-tricarboxylic acid (TTCA) and thiazole-4,5-dicarboxylic acid (TDCA) as markers for pheomelanin and pyrrole-2,3-dicarboxylic acid (PDCA) as a marker for 5,6-dihydroxyindole-derived eumelanin. Those four degradation products can be easily separated by HPLC and analyzed with ultraviolet detection. The alkaline H(2)O(2) oxidation method is simple, reproducible and applicable to all pigmented tissues. Its application to characterize eumelanin and pheomelanin in human hair shows that PTCA and TTCA serve as specific markers for eumelanin and pheomelanin, respectively, although some caution is needed regarding the artificial production of TTCA from eumelanic tissue proteins.
authors.affiliation: Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Aichi, Japan.
authors.forename: Shosuke
authors.initials: S
authors.lastname: Ito
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Nakanishi
authors.forename: Robert K
authors.initials: RK
authors.lastname: Valenzuela
authors.forename: Murray H
authors.initials: MH
authors.lastname: Brilliant
authors.forename: Ludger
authors.initials: L
authors.lastname: Kolbe
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Wakamatsu
mesh_terms: D000293:Adolescent; D000328:Adult; D000468:Alkalies / Q000737:chemistry*; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006197:Hair / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008297:Male; D008543:Melanins / Q000032:analysis* / Q000737:chemistry; D051379:Mice; D009928:Organ Specificity; D010084:Oxidation-Reduction; D011758:Pyrroles / Q000032:analysis; D013997:Time Factors; D055815:Young Adult
chemical_list: D000468:Alkalies; D015415:Biomarkers; D008543:Melanins; D011758:Pyrroles; C018362:pheomelanin; C041877:eumelanin; C071226:pyrrole-2,3,5-tricarboxylic acid; D006861:Hydrogen Peroxide