PMID- 35933709
OWN - NLM
STAT- MEDLINE
DCOM- 20221028
LR  - 20230104
IS  - 1755-148X (Electronic)
IS  - 1755-1471 (Print)
IS  - 1755-1471 (Linking)
VI  - 35
IP  - 6
DP  - 2022 Nov
TI  - 5,6-Dihydroxyindole eumelanin content in human skin with varying degrees of 
      constitutive pigmentation.
PG  - 622-626
LID - 10.1111/pcmr.13062 [doi]
AB  - Human skin contains two distinct components: brown to black, insoluble eumelanin 
      and light colored, alkaline-soluble pheomelanin. Eumelanin consists of 
      5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) 
      moieties, while pheomelanin consists of benzothiazine (BT) and benzothiazole (BZ) 
      moieties. These melanin monomer units can be quantitatively analyzed through 
      specific degradation products by high-performance liquid chromatography (HPLC). 
      Alkaline hydrogen peroxide oxidation (AHPO) of eumelanin gives rise to 
      pyrrole-2,3,5-tricarboxylic acid (PTCA) and pyrrole-2,3-dicarboxylic acid (PDCA) 
      as specific degradation products of the DHICA and DHI moieties, respectively. BZ 
      moiety in pheomelanin can be analyzed as thiazole-2,4,5-tricarboxylic acid 
      (TTCA). By reductive hydrolysis with hydroiodic acid, BT moieties in pheomelanin 
      can be analyzed as 4-amino-3-hydroxyphenylalanine (4-AHP). As a recently improved 
      AHPO-HPLC method enabled a better characterization of PDCA, this prompted us to 
      address the question of DHI to DHICA ratio in human skin samples with varying 
      degrees of constitutive pigmentation ranging from very light to dark. Results 
      showed for the first time the ratio of 4 moieties: DHI 35%, DHICA 41%, BZ 20%, 
      and BT 4%. The ratio is constant regardless of the degree of pigmentation. The 
      high content of DHICA moiety may impart an antioxidant property to the epidermis 
      melanin.
CI  - (c) 2022 The Authors. Pigment Cell & Melanoma Research published by John Wiley 
      & Sons Ltd.
FAU - Del Bino, Sandra
AU  - Del Bino S
AUID- ORCID: 0000-0002-8488-1890
AD  - L'Oreal Research and Innovation, Aulnay-sous-Bois, France.
FAU - Ito, Shosuke
AU  - Ito S
AUID- ORCID: 0000-0001-9182-5144
AD  - Institute for Melanin Chemistry, Fujita Health University, Toyoake, Japan.
FAU - Sok, Juliette
AU  - Sok J
AD  - L'Oreal Research and Innovation, Aulnay-sous-Bois, France.
FAU - Wakamatsu, Kazumasa
AU  - Wakamatsu K
AUID- ORCID: 0000-0003-1748-9001
AD  - Institute for Melanin Chemistry, Fujita Health University, Toyoake, Japan.
LA  - eng
PT  - Journal Article
DEP - 20220826
PL  - England
TA  - Pigment Cell Melanoma Res
JT  - Pigment cell & melanoma research
JID - 101318927
RN  - 12627-86-0 (eumelanin)
RN  - 0 (Melanins)
RN  - Z3OC8499KG (5,6-dihydroxyindole)
RN  - BBX060AN9V (Hydrogen Peroxide)
RN  - 0 (Antioxidants)
RN  - 0 (Pyrroles)
RN  - 0 (Benzothiazoles)
RN  - 0 (Tricarboxylic Acids)
SB  - IM
MH  - Humans
MH  - *Melanins/metabolism
MH  - *Hydrogen Peroxide
MH  - Antioxidants
MH  - Pigmentation
MH  - Pyrroles
MH  - Benzothiazoles
MH  - Tricarboxylic Acids
PMC - PMC9804219
OTO - NOTNLM
OT  - 5,6-dihydroxyindole
OT  - 5,6-dihydroxyindole-2-carboxylic acid
OT  - eumelanin
OT  - pheomelanin
OT  - skin
COIS- SDB and JS are full time employees of L'Oreal, Research and Innovation, Aulnay, 
      France. SI has a consulting contract with L'Oreal, Research and Innovation. KW 
      declares no conflict of interest.
EDAT- 2022/08/08 06:00
MHDA- 2022/10/29 06:00
PMCR- 2022/12/31
CRDT- 2022/08/07 14:00
PHST- 2022/07/21 00:00 [revised]
PHST- 2022/05/31 00:00 [received]
PHST- 2022/08/03 00:00 [accepted]
PHST- 2022/08/08 06:00 [pubmed]
PHST- 2022/10/29 06:00 [medline]
PHST- 2022/08/07 14:00 [entrez]
PHST- 2022/12/31 00:00 [pmc-release]
AID - PCMR13062 [pii]
AID - 10.1111/pcmr.13062 [doi]
PST - ppublish
SO  - Pigment Cell Melanoma Res. 2022 Nov;35(6):622-626. doi: 10.1111/pcmr.13062. Epub 
      2022 Aug 26.