PMID- 9187303
OWN - NLM
STAT- MEDLINE
DCOM- 19970701
LR  - 20190610
IS  - 0006-3002 (Print)
IS  - 0006-3002 (Linking)
VI  - 1346
IP  - 1
DP  - 1997 May 17
TI  - Diffusible melanin-related metabolites are potent inhibitors of lipid 
      peroxidation.
PG  - 61-8
AB  - Although it has long been known that epidermal melanocytes produce and excrete a 
      number of melanin-related metabolites, including 5.6-dihydroxyindole (DHI), 
      5,6-dihydroxyindole-2-carboxylic acid (DHICA), and 5-S-cysteinyldopa (CD), the 
      possible functional significance of these compounds has been so far largely 
      overlooked. We report now evidence that DHI, DHICA and CD exert potent inhibitory 
      effects in different in vitro models of lipid peroxidation. The compounds, at 100 
      microM concentration, substantially decreased malondialdehyde (MDA) formation by 
      lipid peroxidation in rat brain cortex homogenates. At 1.2 microM concentration, 
      DHI proved as effective as alpha-tocopherol (alpha-T), one of the most potent 
      endogenous antioxidants, in suppressing azo-induced peroxidation of linoleic acid 
      in phosphate buffer (pH 7.4), containing 0.10 M SDS, whereas CD and DHICA at the 
      same concentration were less active. DHI, CD and DHICA (all in the range 25 
      microM-0.5 mM) were also found to inhibit Fe (II)/EDTA-induced oxidation of 0.5 
      mM arachidonic acid at pH 7.4, as well as MDA formation by iron-promoted 
      degradation of 0.5 mM 15-hydroperoxy-5,8,11, 13-eicosatetraenoic acid (15-HPETE). 
      In both cases the inhibitory effects were much greater than those of ascorbic 
      acid and glutathione. These results point to melanin precursors as a novel class 
      of biological antioxidants which may contribute to defense mechanisms against 
      oxidative injury in human skin.
FAU - Memoli, S
AU  - Memoli S
AD  - Department of Organic and Biological Chemistry, University of Naples Federico II, 
      Italy.
FAU - Napolitano, A
AU  - Napolitano A
FAU - d'Ischia, M
AU  - d'Ischia M
FAU - Misuraca, G
AU  - Misuraca G
FAU - Palumbo, A
AU  - Palumbo A
FAU - Prota, G
AU  - Prota G
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Netherlands
TA  - Biochim Biophys Acta
JT  - Biochimica et biophysica acta
JID - 0217513
RN  - 0 (Indoles)
RN  - 0 (Linoleic Acids)
RN  - 0 (Melanins)
RN  - 0 (Protein Precursors)
RN  - 0 (Thiobarbituric Acid Reactive Substances)
RN  - 19641-92-0 (Cysteinyldopa)
RN  - 4790-08-3 (5,6-dihydroxy-2-indolylcarboxylic acid)
RN  - 9G34HU7RV0 (Edetic Acid)
RN  - 9KJL21T0QJ (Linoleic Acid)
RN  - Z3OC8499KG (5,6-dihydroxyindole)
SB  - IM
MH  - Animals
MH  - Cerebral Cortex/drug effects/metabolism
MH  - Cysteinyldopa/*pharmacology
MH  - Edetic Acid
MH  - In Vitro Techniques
MH  - Indoles/*pharmacology
MH  - Linoleic Acid
MH  - Linoleic Acids/metabolism
MH  - Lipid Peroxidation/*drug effects
MH  - Male
MH  - Melanins/*metabolism
MH  - Protein Precursors/*pharmacology
MH  - Rats
MH  - Rats, Wistar
MH  - Thiobarbituric Acid Reactive Substances/analysis
EDAT- 1997/05/17 00:00
MHDA- 1997/05/17 00:01
CRDT- 1997/05/17 00:00
PHST- 1997/05/17 00:00 [pubmed]
PHST- 1997/05/17 00:01 [medline]
PHST- 1997/05/17 00:00 [entrez]
AID - S0005-2760(97)00018-0 [pii]
AID - 10.1016/s0005-2760(97)00018-0 [doi]
PST - ppublish
SO  - Biochim Biophys Acta. 1997 May 17;1346(1):61-8. doi: 
      10.1016/s0005-2760(97)00018-0.