Journal Mobile Options
Table of Contents
Vol. 9, No. 3-4, 2000
Issue release date: May–August 2000
Section title: Original Paper
Biol Signals Recept 2000;9:137–159
(DOI:10.1159/000014635)

Significance of Melatonin in Antioxidative Defense System: Reactions and Products

Tan D.-X. · Manchester L.C. · Reiter R.J. · Qi W.-B. · Karbownik M. · Calvo J.R.
aDepartment of Cellular and Structural Biology, The University of Texas Health Science Center, San Antonio, Tex., USA; bDepartment of Thyroidology, Institute of Endocrinology, Medical University, Lodz, Poland

Do you have an account?

Register and profit from personalized services (MyKarger) Login Information

Please create your User ID & Password





Contact Information









I have read the Karger Terms and Conditions and agree.

Register and profit from personalized services (MyKarger) Login Information

Please create your User ID & Password





Contact Information









I have read the Karger Terms and Conditions and agree.

To view the fulltext, please log in

To view the pdf, please log in

Buy

  • FullText & PDF
  • Unlimited re-access via MyKarger (new!)
  • Unrestricted printing, no saving restrictions for personal use
  • Reduced rates with a PPV account
read more

Direct: USD 38.00
Account: USD 26.50

Select

Rent/Cloud

  • Rent for 48h to view
  • Buy Cloud Access for unlimited viewing via different devices
  • Synchronizing in the ReadCube Cloud
  • Printing and saving restrictions apply

Rental: USD 8.50
Cloud: USD 20.00

Select

Subscribe

  • Automatic perpetual access to all articles of the subscribed year(s)
  • Unlimited re-access via Subscriber Login or MyKarger
  • Unrestricted printing, no saving restrictions for personal use
read more

Subcription rates


Select


Article / Publication Details

First-Page Preview
Abstract of Original Paper

Published online: 7/20/2000

Number of Print Pages: 23
Number of Figures: 10
Number of Tables: 1

ISSN: 1424-862X (Print)
eISSN: 1424-8638 (Online)

For additional information: http://www.karger.com/NSG

Abstract

Melatonin is a potent endogenous free radical scavenger, actions that are independent of its many receptor-mediated effects. In the last several years, hundreds of publications have confirmed that melatonin is a broad-spectrum antioxidant. Melatonin has been reported to scavenge hydrogen peroxide (H2O2), hydroxyl radical (HO·), nitric oxide (NO·), peroxynitrite anion (ONOO), hypochlorous acid (HOCl), singlet oxygen (1O2), superoxide anion (O2·) and peroxyl radical (LOO·), although the validity of its ability to scavenge O2· and LOO· is debatable. Regardless of the radicals scavenged, melatonin prevents oxidative damage at the level of cells, tissues, organs and organisms. The antioxidative mechanisms of melatonin seem different from classical antioxidants such as vitamin C, vitamin E and glutathione. As electron donors, classical antioxidants undergo redox cycling; thus, they have the potential to promote oxidation as well as prevent it. Melatonin, as an electron-rich molecule, may interact with free radicals via an additive reaction to form several stable end-products which are excreted in the urine. Melatonin does not undergo redox cycling and, thus, does not promote oxidation as shown under a variety of experimental conditions. From this point of view, melatonin can be considered a suicidal or terminal antioxidant which distinguishes it from the opportunistic antioxidants. Interestingly, the ability of melatonin to scavenge free radicals is not in a ratio of mole to mole. Indeed, one melatonin molecule scavenges two HO·. Also, its secondary and tertiary metabolites, for example, N1-acetyl-N2-formyl-5-methoxykynuramine, N-acetyl-5-methoxykynuramine and 6-hydroxymelatonin, which are believed to be generated when melatonin interacts with free radicals, are also regarded as effective free radical scavengers. The continuous free radical scavenging potential of the original molecule (melatonin) and its metabolites may be defined as a scavenging cascade reaction. Melatonin also synergizes with vitamin C, vitamin E and glutathione in the scavenging of free radicals. Melatonin has been detected in vegetables, fruits and a variety of herbs. In some plants, especially in flowers and seeds (the reproductive organs which are most vulnerable to oxidative insults), melatonin concentrations are several orders of magnitude higher than measured in the blood of vertebrates. Melatonin in plants not only provides an alternative exogenous source of melatonin for herbivores but also suggests that melatonin may be an important antioxidant in plants which protects them from a hostile environment that includes extreme heat, cold and pollution, all of which generate free radicals.


  

Author Contacts

Dr. Russel J. Reiter
Department of Cellular and Structural Biology
Mail Code 7762, The University of Texas Health Science Center
7703 Floyd Curl Drive, San Antonio, TX 78229-3900 (USA)
Tel. +1 210 567 3859, Fax +1 210 567 6948, E-Mail reiter@uthscsa.edu

  

Article Information

Received: Submitted: November 6, 1999
Accepted: November 26, 1999
Number of Print Pages : 23
Number of Figures : 10, Number of Tables : 1, Number of References : 138

  

Publication Details

Biological Signals and Receptors

Vol. 9, No. 3-4, Year 2000 (Cover Date: May-August 2000)

Journal Editor: S.F. Pang, Hong Kong; P.A. Ward, Ann Arbor, Mich.; D.P. Cardinali, Buenos Aires
ISSN: 1422–4933 (print), 1422–4992 (Online)

For additional information: http://www.karger.com/journals/bsi


Article / Publication Details

First-Page Preview
Abstract of Original Paper

Published online: 7/20/2000

Number of Print Pages: 23
Number of Figures: 10
Number of Tables: 1

ISSN: 1424-862X (Print)
eISSN: 1424-8638 (Online)

For additional information: http://www.karger.com/NSG


Copyright / Drug Dosage

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.