Melatonin as an antioxidant: under promises but over delivers

Journal of Pineal Research, Год журнала: 2016, Номер 61(3), С. 253 - 278

Опубликована: Авг. 8, 2016

Melatonin is uncommonly effective in reducing oxidative stress under a remarkably large number of circumstances. It achieves this action via variety means: direct detoxification reactive oxygen and nitrogen species indirectly by stimulating antioxidant enzymes while suppressing the activity pro-oxidant enzymes. In addition to these well-described actions, melatonin also reportedly chelates transition metals, which are involved Fenton/Haber-Weiss reactions; doing so, reduces formation devastatingly toxic hydroxyl radical resulting reduction stress. Melatonin's ubiquitous but unequal intracellular distribution, including its high concentrations mitochondria, likely aid capacity resist cellular apoptosis. There credible evidence suggest that should be classified as mitochondria-targeted antioxidant. prevent damage associated physiological debilitation well documented numerous experimental ischemia/reperfusion (hypoxia/reoxygenation) studies especially brain (stroke) heart (heart attack). Melatonin, antiradical mechanisms, toxicity noxious prescription drugs methamphetamine, drug abuse. Experimental findings indicate renders treatment-resistant cancers sensitive various therapeutic agents may useful, due multiple delaying perhaps treating age-related diseases dehumanizing conditions. has been effectively used combat stress, inflammation apoptosis restore tissue function human trials; efficacy supports more extensive use wider studies. The high-safety profile bolsters conclusion. current feeling authors that, view widely diverse beneficial functions have reported for melatonin, merely epiphenomena fundamental, yet-to-be identified basic action(s) ancient molecule.

Язык: Английский

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Melatonin as a natural ally against oxidative stress: a physicochemical examination

Journal of Pineal Research, Год журнала: 2011, Номер 51(1), С. 1 - 16

Опубликована: Июнь 14, 2011

Abstract: Oxidative stress has been proven to be related the onset of a large number health disorders. This chemical is triggered by an excess free radicals, which are generated in cells because wide variety exogenous and endogenous processes. Therefore, finding strategies for efficiently detoxifying radicals become subject great interest, from both academic practical points view. Melatonin ubiquitous versatile molecule that exhibits most desirable characteristics good antioxidant. The amount data gathered so far regarding protective action melatonin against oxidative overwhelming. However, rather little known concerning mechanisms involved this activity. review summarizes current progress understanding physicochemical insights radical–scavenging activity melatonin. Thus far, there general agreement electron transfer hydrogen main reactions with radicals. relative importance other also analyzed. nature reacting radical influence on different these reactions. point discussed detail review. Based available data, it concluded protects mechanisms. Moreover, proposed even though referred as expression darkness, perhaps could light health.

Язык: Английский

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Extrapineal melatonin: sources, regulation, and potential functions

Cellular and Molecular Life Sciences, Год журнала: 2014, Номер 71(16), С. 2997 - 3025

Опубликована: Фев. 19, 2014

Язык: Английский

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Functions of melatonin in plants: a review

Journal of Pineal Research, Год журнала: 2015, Номер 59(2), С. 133 - 150

Опубликована: Июнь 19, 2015

The number of studies on melatonin in plants has increased significantly recent years. This molecule, with a large set functions animals, also shown great potential plant physiology. review outlines the main physiology higher plants. Its role as antistress agent against abiotic stressors, such drought, salinity, low and high ambient temperatures, UV radiation toxic chemicals, is analyzed. latest data their plant-pathogen interactions are discussed. Both biotic stresses produce significant increase endogenous levels, indicating its possible effector these situations. existence circadian rhythms levels been demonstrated some species, data, although limited, suggest central this molecule day/night cycles Finally, another aspect that led to volume research involvement aspects development regulation. Although hormone still far from being fully established, processes growth, rhizogenesis, photosynthesis seems evident. multiple changes gene expression caused by point multiregulatory capable coordinating many development. last aspect, together an alleviating-stressor agent, suggests excellent prospect for crop improvement.

Язык: Английский

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Melatonin: a well‐documented antioxidant with conditional pro‐oxidant actions

Journal of Pineal Research, Год журнала: 2014, Номер 57(2), С. 131 - 146

Опубликована: Июль 25, 2014

Abstract Melatonin ( N ‐acetyl‐5‐methoxytryptamine), an indoleamine produced in many organs including the pineal gland, was initially characterized as a hormone primarily involved circadian regulation of physiological and neuroendocrine function. Subsequent studies found that melatonin its metabolic derivatives possess strong free radical scavenging properties. These metabolites are potent antioxidants against both ROS (reactive oxygen species) RNS nitrogen species). The mechanisms by which protect radicals oxidative stress include direct products, induction expression antioxidant enzymes, reduction activation pro‐oxidant maintenance mitochondrial homeostasis. In vitro vivo studies, has been shown to reduce damage lipids, proteins DNA under very wide set conditions where toxic known be produced. Although vast majority proved capacity derivatives, few using cultured cells promoted generation at pharmacological concentrations μ m range) several tumor nontumor cells; thus, functioned conditional pro‐oxidant. Mechanistically, may stimulate production through interaction with calmodulin. Also, interact complex III or transition pore promote production. Whether functions is not well documented; whether reported actions come into play live organisms remains established.

Язык: Английский

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Melatonin membrane receptors in peripheral tissues: Distribution and functions

Molecular and Cellular Endocrinology, Год журнала: 2012, Номер 351(2), С. 152 - 166

Опубликована: Янв. 10, 2012

Язык: Английский

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Roles of melatonin in abiotic stress resistance in plants

Journal of Experimental Botany, Год журнала: 2014, Номер 66(3), С. 647 - 656

Опубликована: Авг. 14, 2014

In recent years melatonin has emerged as a research highlight in plant studies. Melatonin different functions many aspects of growth and development. The most frequently mentioned are related to abiotic stresses such drought, radiation, extreme temperature, chemical stresses. This review mainly focuses on the regulatory effects when plants face harsh environmental conditions. Evidence indicates that stress can increase level endogenous plants. Overexpression biosynthetic genes elevates levels transgenic show enhanced tolerance Exogenously applied also improve ability tolerate mechanisms by which alleviates discussed.

Язык: Английский

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Functional roles of melatonin in plants, and perspectives in nutritional and agricultural science

Journal of Experimental Botany, Год журнала: 2011, Номер 63(2), С. 577 - 597

Опубликована: Окт. 20, 2011

The presence of melatonin in plants is universal. Evidence has confirmed that a major portion the synthesized by themselves even though homologue classic arylalkylamine N-acetyltransferase (AANAT) not been identified as yet plants. Thus, serotonin N-acetylating enzyme may differ greatly from animal AANAT with regard to sequence and structure. This would imply multiple evolutionary origins enzymes these catalytic properties. A primary function serve first line defence against internal environmental oxidative stressors. much higher levels compared those found animals are thought be compensatory response which lack means mobility, unlike animals, coping harsh environments. Importantly, remarkably high concentrations have measured popular beverages (coffee, tea, wine, beer) crops (corn, rice, wheat, barley, oats). Billions people worldwide consume products daily. beneficial effects on human health derived consumption must considered. also indicates an ability increase production crops. mechanisms involve roles preservation chlorophyll, promotion photosynthesis, stimulation root development. Transgenic enhanced content could probably lead breakthroughs crop agriculture improve general humans.

Язык: Английский

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Mitochondria and chloroplasts as the original sites of melatonin synthesis: a hypothesis related to melatonin's primary function and evolution in eukaryotes

Journal of Pineal Research, Год журнала: 2012, Номер 54(2), С. 127 - 138

Опубликована: Окт. 12, 2012

Abstract Mitochondria and chloroplasts are major sources of free radical generation in living organisms. Because this, these organelles require strong protection from radicals associated oxidative stress. Melatonin is a potent scavenger antioxidant. It meets the criteria as mitochondrial chloroplast Evidence has emerged to show that both mitochondria may have capacity synthesize metabolize melatonin. The activity arylalkylamine N ‐acetyltransferase ( AANAT ), reported rate‐limiting enzyme melatonin synthesis, been identified mitochondria, high levels also found this organelle. From an evolutionary point view, precursor probably purple nonsulfur bacterium, particularly, R hodospirillum rubrum, descendents cyanobacteria. These bacterial species were endosymbionts host proto‐eukaryotes gradually transformed into cellular organelles, is, chloroplasts, respectively, thereby giving rise eukaryotic cells. Of special importance, bacteria . rubrum ) cyanobacteria activities required for synthesis detected primitive species. our hypothesis original sites early stage endosymbiotic organisms; synthetic was carried eukaryotes by above‐mentioned bacteria. Moreover, their biosynthetic capacities preserved during evolution. In most, if not all cells, continue be primary generation. production other compartments derived chloroplasts. On basis hypothesis, it possible explain why plants typically higher than do animals. plants, likely melatonin, while animal cells contain only mitochondria. produced used protect important against stress preserve physiological functions. superior beneficial effects frequently reported.

Язык: Английский

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Long‐term exogenous application of melatonin delays drought‐induced leaf senescence in apple

Journal of Pineal Research, Год журнала: 2012, Номер 54(3), С. 292 - 302

Опубликована: Окт. 1, 2012

Abstract To examine the potential roles of melatonin in drought tolerance, we tested effects its long‐term exogenous application on ‘Hanfu’ apple ( Malus domestica Borkh.). When 100 μ m was added to soils under conditions, resultant oxidative stress eased and leaf senescence delayed. This molecule significantly reduced chlorophyll degradation suppressed up‐regulation senescence‐associated gene 12 SAG ) pheophorbide a oxygenase PAO ). Such treatment also alleviated inhibition photosynthesis brought by stress. We investigated quenching efficiency Photosystem II PSII photochemistry dark light conditions found that helped maintain better function drought. The addition controlled burst hydrogen peroxide, possibly through direct scavenging enhancing activities antioxidative enzymes capacity ascorbate–glutathione cycle. Thus, understanding this effect tolerance introduces new possibilities use compound for agricultural purposes.

Язык: Английский

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