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On the free radical scavenging activities of melatonin's metabolites, AFMK and AMK.
J Pineal Res. 2013 Apr; 54(3):245-57.JP

Abstract

The reactions of N(1) -acetyl-N(2) -formyl-5-methoxykynuramine (AFMK) and N(1) -acetyl-5-methoxykynuramine (AMK) with (•) OH, (•) OOH, and •OOCCl3 radicals have been studied using the density functional theory. Three mechanisms of reaction have been considered: radical adduct formation (RAF), hydrogen transfer (HT), and single electron transfer (SET). Their relative importance for the free radical scavenging activity of AFMK and AMK has been assessed. It was found that AFMK and AMK react with •OH at diffusion-limited rates, regardless of the polarity of the environment, which supports their excellent •OH radical scavenging activity. Both compounds were found to be also very efficient for scavenging •OOCCl3 , but rather ineffective for scavenging •OOH. Regarding their relative activity, it was found that AFMK systematically is a poorer scavenger than AMK and melatonin. In aqueous solution, AMK was found to react faster than melatonin with all the studied free radicals, while in nonpolar environments, the relative efficiency of AMK and melatonin as free radical scavengers depends on the radical with which they are reacting. Under such conditions, melatonin is predicted to be a better •OOH and •OOCCl3 scavenger than AMK, while AMK is predicted to be slightly better than melatonin for scavenging •OH. Accordingly it seems that melatonin and its metabolite AMK constitute an efficient team of scavengers able of deactivating a wide variety of reactive oxygen species, under different conditions. Thus, the presented results support the continuous protection exerted by melatonin, through the free radical scavenging cascade.

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Authors+Show Affiliations

Galano A
Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, DF, México. agal@xanum.uam.mx
Tan DX
No affiliation info available
Reiter RJ
No affiliation info available

MeSH

Free Radical ScavengersKineticsKynuramineMelatoninModels, MolecularThermodynamics

Pub Type(s)

Journal Article
Review

Language

eng

PubMed ID

22998574

Citation

Galano, Annia, et al. "On the Free Radical Scavenging Activities of Melatonin's Metabolites, AFMK and AMK." Journal of Pineal Research, vol. 54, no. 3, 2013, pp. 245-57.
Galano A, Tan DX, Reiter RJ. On the free radical scavenging activities of melatonin's metabolites, AFMK and AMK. J Pineal Res. 2013;54(3):245-57.
Galano, A., Tan, D. X., & Reiter, R. J. (2013). On the free radical scavenging activities of melatonin's metabolites, AFMK and AMK. Journal of Pineal Research, 54(3), 245-57. https://doi.org/10.1111/jpi.12010
Galano A, Tan DX, Reiter RJ. On the Free Radical Scavenging Activities of Melatonin's Metabolites, AFMK and AMK. J Pineal Res. 2013;54(3):245-57. PubMed PMID: 22998574.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - On the free radical scavenging activities of melatonin's metabolites, AFMK and AMK. AU - Galano,Annia, AU - Tan,Dun Xian, AU - Reiter,Russel J, Y1 - 2012/09/23/ PY - 2012/08/14/received PY - 2012/08/14/accepted PY - 2012/9/25/entrez PY - 2012/9/25/pubmed PY - 2013/11/20/medline SP - 245 EP - 57 JF - Journal of pineal research JO - J Pineal Res VL - 54 IS - 3 N2 - The reactions of N(1) -acetyl-N(2) -formyl-5-methoxykynuramine (AFMK) and N(1) -acetyl-5-methoxykynuramine (AMK) with (•) OH, (•) OOH, and •OOCCl3 radicals have been studied using the density functional theory. Three mechanisms of reaction have been considered: radical adduct formation (RAF), hydrogen transfer (HT), and single electron transfer (SET). Their relative importance for the free radical scavenging activity of AFMK and AMK has been assessed. It was found that AFMK and AMK react with •OH at diffusion-limited rates, regardless of the polarity of the environment, which supports their excellent •OH radical scavenging activity. Both compounds were found to be also very efficient for scavenging •OOCCl3 , but rather ineffective for scavenging •OOH. Regarding their relative activity, it was found that AFMK systematically is a poorer scavenger than AMK and melatonin. In aqueous solution, AMK was found to react faster than melatonin with all the studied free radicals, while in nonpolar environments, the relative efficiency of AMK and melatonin as free radical scavengers depends on the radical with which they are reacting. Under such conditions, melatonin is predicted to be a better •OOH and •OOCCl3 scavenger than AMK, while AMK is predicted to be slightly better than melatonin for scavenging •OH. Accordingly it seems that melatonin and its metabolite AMK constitute an efficient team of scavengers able of deactivating a wide variety of reactive oxygen species, under different conditions. Thus, the presented results support the continuous protection exerted by melatonin, through the free radical scavenging cascade. SN - 1600-079X UR - https://www.unboundmedicine.com/medline/citation/22998574/On_the_free_radical_scavenging_activities_of_melatonin's_metabolites_AFMK_and_AMK_ L2 - https://doi.org/10.1111/jpi.12010 DB - PRIME DP - Unbound Medicine ER -