Diversity of human hair pigmentation as studied by chemical analysis of eumelanin and pheomelanin

  title={Diversity of human hair pigmentation as studied by chemical analysis of eumelanin and pheomelanin},
  author={Shosuke Ito and Kazumasa Wakamatsu},
  journal={Journal of the European Academy of Dermatology and Venereology},
  • S. Ito, K. Wakamatsu
  • Published 1 December 2011
  • Biology
  • Journal of the European Academy of Dermatology and Venereology
Hair colour is one of the most conspicuous phenotypes in humans, ranging from black, brown, blond to red. [] Key Method Pheomelanin can also be analysed as 4-amino-3-hydroxyphenylalanine (4-AHP) after hydroiodic acid hydrolysis. Using those methods, we evaluated the contents of eumelanin and pheomelanin (the 'chemical' phenotype) in human hairs of black, dark brown, brown, light brown, blond and red colour (the 'visual' phenotype). Eumelanin contents decrease in that order, with a trace but constant level of…

Properties of melanin pigments for the definition of mechanisms of (photo)toxicity in red hair phenotype and development of strategies of (photo)protection.

The research work carried out during the PhD course and reported in this thesis was directed at investigating the light-independent effects of purified human hair melanins on keratinocyte cell cultures with particular attention to their pro-oxidant properties and at defining the origin of the broadband absorption spectrum of eumelanin, which underpins their protective shielding effect.

Neutral pH and copper ions promote eumelanogenesis after the dopachrome stage

The results indicate that an acidic pH greatly suppresses the late stages of eumelanogenesis and that Cu2+ ions accelerate the conversion of DC to DHICA and its subsequent oxidation.

Chemical and biochemical control of skin pigmentation with special emphasis on mixed melanogenesis

Various factors affecting mixed melanogenesis are focused on including chemical regulation of melanin synthesis, melanosomal pH regulation during normal melanogenesis and effect on Mixed melanogenesis, and mechanisms of melanosomes pH control (proton pumps, channels, transporters, and signaling pathways).

Genome-wide association analysis identifies potential regulatory genes for eumelanin pigmentation in chicken plumage.

It is inferred that genes, including NUAK family kinase 1 (NUAK1) and sonic hedgehog (SHH) may play roles in the development of neural crest cells or melanoblasts during the embryonic period, which may also affect the eumelanin pigmentation.

Red human hair pheomelanin is a potent pro‐oxidant mediating UV‐independent contributory mechanisms of melanomagenesis

The unprecedented property of purified red human hair pheomelanin (RHP) is disclosed to promote the oxygen‐dependent depletion of major cell antioxidants, for example glutathione and NADH; and the autoxidative formation of melanin pigments from their precursors.

Pheomelanin‐induced oxidative stress: bright and dark chemistry bridging red hair phenotype and melanoma

A detailed discussion of the possible UV‐dependent and UV‐independent chemical mechanisms underlying pheomelanin‐mediated oxidative stress, with special reference to the oxygen‐dependent depletion of glutathione and other cell antioxidants, and possible concerted strategies for melanoma prevention in the red hair phenotype are proposed.

A Melanin-Related Phenolic Polymer with Potent Photoprotective and Antioxidant Activities for Dermo-Cosmetic Applications

Protective effect of a polymer obtained starting from the methyl ester of DHICA (MeDHICA-melanin) against Ultraviolet A (UVA)-induced oxidative stress in immortalized human keratinocytes (HaCaT).

The Genetics of Human Skin and Hair Pigmentation.

The responsible polymorphisms within these pigmentation genes appear at different population frequencies, can be used as ancestry-informative markers, and provide insight into the evolutionary selective forces that have acted to create this human diversity.

Evolution of human skin pigmentation. Genetic factors underlying variability and association with eye and hair color.

In this review we present an updated overview of the main current hypotheses for the evolution of skin color and the genetic factors underlying its variability, as well as a brief remark of the



Chemical characterization of melanins in sheep wool and human hair.

It was demonstrated that black wool in Asiatic sheep contains eumelanin with the DHICA content similar to black mouse melanin, while black to brown melanins from human hair contain much lower ratios of DHICA-derived units, comparable to the slaty mutation in mice.

Quantitative analysis of eumelanin and pheomelanin in humans, mice, and other animals: a comparative review.

Eumelanin is always the major constituent of epidermal melanin, and the skin color appears to be determined by the quantity of melanin produced but not by the quality.

Chemical characterization of hair melanins in various coat-color mutants of mice.

Results indicate that the methodology, high-performance liquid chromatography and spectrophotometric methods combined, may be useful in chemically characterizing melanin pigments produced in follicular melanocytes, and suggest that the brown-type eu- and pheomelanins have lower degrees of polymerization than the black- type eumelan ins.

Spectrophotometric characterization of eumelanin and pheomelanin in hair.

The results indicate that the A500 value can be used to quantify the total combined amount of eu- and pheomelanins, and the A650/A500 ratio can serve as a parameter to estimate the eumelanin/total melanin ratio.

Human hair melanins: what we have learned and have not learned from mouse coat color pigmentation

What the authors have/have not learned from mouse coat color pigmentation is discussed, with special emphasis on the significant roles of pH and the level of cysteine in melanosomes in controlling melanogenesis.

Interaction of major coat color gene functions in mice as studied by chemical analysis of eumelanin and pheomelanin.

Phenotypes of chinchilla mice that are wild type or mutant at the brown and/or slaty, loci indicate that functioning TRP2 and TRP1 are necessary, in addition to high levels of tyrosinase, for a full production of eumelanin.

Usefulness of alkaline hydrogen peroxide oxidation to analyze eumelanin and pheomelanin in various tissue samples: application to chemical analysis of human hair melanins

Alkaline H2O2 oxidation method is simple, reproducible and applicable to all pigmented tissues and shows that PTCA and TTCA serve as specific markers for eumelanin and pheomelan in human hair, although some caution is needed regarding the artificial production of TTCA from eumELanic tissue proteins.

Chemistry of Mixed Melanogenesis—Pivotal Roles of Dopaquinone †

P Pulse radiolysis studies of early stages of melanogenesis indicate that mixed melanogenesis proceeds in three distinct stages—the initial production of cysteinyldopas, followed by their oxidation to produce pheomelanin, followed finally by the production of eumelan in.

Absence of TRP-2 in melanogenic melanocytes of human hair.

The results suggest that eumelanogenesis as well as brown and black colour do not require TRP-2 expression in human hair, and that the absence of detectable level of TRp-2 is due to transcriptional control in active melanocytes of human eumalanic hair bulbs.