Oxidation of melatonin by taurine chloramine

Ximenes, Valdecir Farias; Padovan, Camila Z.; Carvalho, Danielle Almeida de; Fernandes, João Roberto

doi:10.1111/j.1600-079x.2010.00772.x

Cited by 11 publications

(9 citation statements)

References 46 publications

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“…N 1 -Acetyl- N 2 -formyl-5-methoxykynuramine (AFMK) is a product of melatonin oxidation, which can involve both enzymatic and non-enzymatic processes [ 279 , 280 , 281 , 282 , 283 , 284 , 285 , 286 ]. AFMK has an excellent ability as a • OH scavenger [ 287 , 288 , 289 , 290 ].…”

Section: Antioxidant Protectionmentioning

confidence: 99%

Melatonin: A Versatile Protector against Oxidative DNA Damage

2018

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Oxidative damage to DNA has important implications for human health and has been identified as a key factor in the onset and development of numerous diseases. Thus, it is evident that preventing DNA from oxidative damage is crucial for humans and for any living organism. Melatonin is an astonishingly versatile molecule in this context. It can offer both direct and indirect protection against a wide variety of damaging agents and through multiple pathways, which may (or may not) take place simultaneously. They include direct antioxidative protection, which is mediated by melatonin’s free radical scavenging activity, and also indirect ways of action. The latter include, at least: (i) inhibition of metal-induced DNA damage; (ii) protection against non-radical triggers of oxidative DNA damage; (iii) continuous protection after being metabolized; (iv) activation of antioxidative enzymes; (v) inhibition of pro-oxidative enzymes; and (vi) boosting of the DNA repair machinery. The rather unique capability of melatonin to exhibit multiple neutralizing actions against diverse threatening factors, together with its low toxicity and its ability to cross biological barriers, are all significant to its efficiency for preventing oxidative damage to DNA.

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Section: Antioxidant Protectionmentioning

confidence: 99%

Melatonin: A Versatile Protector against Oxidative DNA Damage

2018

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“…In addition, oxidation of melatonin was partially inhibited by catalase or SOD . Finally, it has been reported that taurine, the most abundant free amino acid in leukocytes, undergoes an oxidation to taurine chloramines by HClO, and this compound oxidizes melatonin to 2‐hydroxymelatonin and AFMK .…”

Section: Neutrophilsmentioning

confidence: 99%

The role of melatonin in the cells of the innate immunity: a review

Calvo

González-Yanes

Maldonado

2013

Journal of Pineal Research

374

287

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Melatonin is the major secretory product synthesized and secreted by the pineal gland and shows both a wide distribution within phylogenetically distant organisms from bacteria to humans and a great functional versatility. In recent years, a considerable amount of experimental evidence has accumulated showing a relationship between the nervous, endocrine, and immune systems. The molecular basis of the communication between these systems is the use of a common chemical language. In this framework, currently melatonin is considered one of the members of the neuroendocrineimmunological network. A number of in vivo and in vitro studies have documented that melatonin plays a fundamental role in neuroimmunomodulation. Based on the information published, it is clear that the majority of the present data in the literature relate to lymphocytes; thus, they have been rather thoroughly investigated, and several reviews have been published related to the mechanisms of action and the effects of melatonin on lymphocytes. However, few studies concerning the effects of melatonin on cells belonging to the innate immunity have been reported. Innate immunity provides the early line of defense against microbes and consists of both cellular and biochemical mechanisms. In this review, we have focused on the role of melatonin in the innate immunity. More specifically, we summarize the effects and action mechanisms of melatonin in the different cells that belong to or participate in the innate immunity, such as monocytes-macrophages, dendritic cells, neutrophils, eosinophils, basophils, mast cells, and natural killer cells.

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“…The rate constants were (pH 5.0) 1.1 × 10 4 M −1 s −1 , (pH 7.0) 9.5 × 10 1 M −1 s −1 and (pH 9.0) 1.7 × 10 1 M −1 s −1 . The pH dependence can be explained by taking into account the higher reactivity of the dihalogenated forms, as has been demonstrated for Tau-NCl 2 [ 45 ].…”

Section: Resultsmentioning

confidence: 99%

Taurine Bromamine: Reactivity of an Endogenous and Exogenous Anti-Inflammatory and Antimicrobial Amino Acid Derivative

et al. 2016

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Taurine bromamine (Tau-NHBr) is produced by the reaction between hypobromous acid (HOBr) and the amino acid taurine. There are increasing number of applications of Tau-NHBr as an anti-inflammatory and microbicidal drug for topical usage. Here, we performed a comprehensive study of the chemical reactivity of Tau-NHBr with endogenous and non-endogenous compounds. Tau-NHBr reactivity was compared with HOBr, hypochlorous acid (HOCl) and taurine chloramine (Tau-NHCl). The second-order rate constants (k2) for the reactions between Tau-NHBr and tryptophan (7.7 × 102 M−1s−1), melatonin (7.3 × 103 M−1s−1), serotonin (2.9 × 103 M−1s−1), dansylglycine (9.5 × 101 M−1s−1), tetramethylbenzidine (6.4 × 102 M−1s−1) and H2O2 (3.9 × M−1s−1) were obtained. Tau-NHBr demonstrated the following selectivity regarding its reactivity with free amino acids: tryptophan > cysteine ~ methionine > tyrosine. The reactivity of Tau-NHBr was strongly affected by the pH of the medium (for instance with dansylglycine: pH 5.0, 1.1 × 104 M−1s−1, pH 7.0, 9.5 × 10 M−1s−1 and pH 9.0, 1.7 × 10 M−1s−1), a property that is related to the formation of the dibromamine form at acidic pH (Tau-NBr2). The formation of singlet oxygen was observed in the reaction between Tau-NHBr and H2O2. Tau-NHBr was also able to react with linoleic acid, but with low efficiency compared with HOBr and HOCl. Compared with HOBr, Tau-NHBr was not able to react with nucleosides. In conclusion, the following reactivity sequence was established: HOBr > HOCl > Tau-NHBr > Tau-NHCl. These findings can be very helpful for researchers interested in biological applications of taurine haloamines.

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Oxidation of melatonin by taurine chloramine

Cited by 11 publications

References 46 publications

Melatonin: A Versatile Protector against Oxidative DNA Damage

Melatonin: A Versatile Protector against Oxidative DNA Damage

The role of melatonin in the cells of the innate immunity: a review

Taurine Bromamine: Reactivity of an Endogenous and Exogenous Anti-Inflammatory and Antimicrobial Amino Acid Derivative

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