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

---

Melatonin: an ancient molecule that makes oxygen metabolically tolerable

Journal of Pineal Research, Год журнала: 2015, Номер 59(4), С. 403 - 419

Опубликована: Авг. 14, 2015

Abstract Melatonin is remarkably functionally diverse with actions as a free radical scavenger and antioxidant, circadian rhythm regulator, anti‐inflammatory immunoregulating molecule, an oncostatic agent. We hypothesize that the initial primary function of melatonin in photosynthetic cyanobacteria, which appeared on Earth 3.5–3.2 billion years ago, was antioxidant. The evolution antioxidant by this organism necessary photosynthesis associated generation toxic‐free radicals. other secondary functions came about much later evolution. also surmise mitochondria chloroplasts may be sites synthesis all eukaryotic cells possess these organelles. This prediction made basis eukaryotes developed from purple nonsulfur bacteria (which produce melatonin) cyanobacteria when they were engulfed early eukaryotes. Thus, we speculate melatonin‐synthesizing retained organelles became chloroplasts, respectively. That are likely formation supported observation organelle contains high levels not impacted blood concentrations. has remarkable array means it thwarts oxidative damage. It, well its metabolites, differentially effective scavenging variety reactive oxygen nitrogen species. Moreover, metabolites modulate large number antioxidative pro‐oxidative enzymes, leading to reduction metabolizing/producing enzymes mediated Keap1‐Nrf2‐ ARE pathway. Beyond direct indirect effects, physiological metabolic advantages enhance ability limit stress.

Язык: Английский

---

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

---

Melatonin as a Potent and Inducible Endogenous Antioxidant: Synthesis and Metabolism

Molecules, Год журнала: 2015, Номер 20(10), С. 18886 - 18906

Опубликована: Окт. 16, 2015

Melatonin is a tryptophan-derived molecule with pleiotropic activities. It present in almost all or organisms. Its synthetic pathway depends on the species which it measured. For example, tryptophan to melatonin differs plants and animals. speculated that machinery eukaryotes was inherited from bacteria as result of endosymbiosis. However, melatonin's mechanisms microorganisms are currently unknown. metabolism highly complex these enzymatic processes having evolved cytochrome C. In addition its degradation, metabolized via pseudoenzymatic free radical interactive processes. The metabolic products overlap often difficult determine process dominant. under oxidative stress, may be featured over others. Because complexity degradative processes, expected additional novel metabolites will identified future investigations. original primary function early life forms such unicellular organisms scavenger antioxidant. During evolution, selected signaling transduce environmental photoperiodic information into an endocrine message multicellular for other purposes well. As antioxidant, exhibits several unique features differ classic antioxidants. These include cascade reaction radicals capacity induced moderate stress. make potent endogenously-occurring antioxidant protects catastrophic

Язык: Английский

---

Melatonin Synthesis and Function: Evolutionary History in Animals and Plants

Frontiers in Endocrinology, Год журнала: 2019, Номер 10

Опубликована: Апрель 17, 2019

Melatonin is an ancient molecule that can be traced back to the origin of life. Melatonin's initial function was likely as a free radical scavenger. presumably evolved in bacteria; it has been measured both α-proteobacteria and photosynthetic cyanobacteria. In early evolution, bacteria were phagocytosed by primitive eukaryotes for their nutrient value. According endosymbiotic theory, ingested eventually developed symbiotic association with host eukaryotes. The into mitochondria while cyanobacteria became chloroplasts organelles retained ability produce melatonin. Since these have persisted present day, all species ever existed or currently exist may continue synthesize melatonin (animals plants) (plants) where functions antioxidant. other functions, including its multiple receptors, later evolution. day animals, via receptor-mediated means, regulation sleep, modulation circadian rhythms, enhancement immunity, multifunctional oncostatic agent, etc., retaining reduce oxidative stress processes are, part, receptor-independent. plants, continues reducing well promoting seed germination growth, improving resistance, stimulating immune system modulating rhythms; single receptor identified land plants controls stomatal closure on leaves. synthetic pathway varies somewhat between animals. amino acid, tryptophan, necessary precursor taxa. tryptophan initially hydroxylated 5-hydroxytryptophan which then decarboxylated formation serotonin. Serotonin either acetylated

Язык: Английский

---

Melatonin and its relationship to plant hormones

Annals of Botany, Год журнала: 2017, Номер 121(2), С. 195 - 207

Опубликована: Авг. 17, 2017

Plant melatonin appears to be a multi-regulatory molecule, similar those observed in animals, with many specific functions plant physiology. In recent years, the number of studies on plants has increased significantly. One most studied actions is its effect biotic and abiotic stress, such as that produced by drought, extreme temperatures, salinity, chemical pollution UV radiation, among others.

Язык: Английский

---

Melatonin as a mitochondria-targeted antioxidant: one of evolution’s best ideas

Cellular and Molecular Life Sciences, Год журнала: 2017, Номер 74(21), С. 3863 - 3881

Опубликована: Сен. 1, 2017

Язык: Английский

---

Melatonin biosynthesis in plants: multiple pathways catalyze tryptophan to melatonin in the cytoplasm or chloroplasts

Journal of Pineal Research, Год журнала: 2016, Номер 61(4), С. 426 - 437

Опубликована: Сен. 7, 2016

Melatonin is an animal hormone as well a signaling molecule in plants. It was first identified plants 1995, and almost all enzymes responsible for melatonin biosynthesis had already been characterized these species. from tryptophan requires four-step reactions. However, six genes, that is, TDC, TPH, T5H, SNAT, ASMT, COMT, have implicated the synthesis of plants, suggesting presence multiple pathways. Two major pathways proposed based on enzyme kinetics: One tryptophan/tryptamine/serotonin/N-acetylserotonin/melatonin pathway, which may occur under normal growth conditions; other tryptophan/tryptamine/serotonin/5-methoxytryptamine/melatonin when produce large amounts serotonin, example, upon senescence. The biosynthetic capacity associated with conversion to serotonin much higher than melatonin, yields low level Many intermediates are produced various subcellular compartments, such cytoplasm, endoplasmic reticulum, chloroplasts, either facilitates or impedes subsequent enzymatic steps. Depending pathways, final sites vary at cytoplasm differentially affect mode action

Язык: Английский

---

Melatonin, a Full Service Anti-Cancer Agent: Inhibition of Initiation, Progression and Metastasis

International Journal of Molecular Sciences, Год журнала: 2017, Номер 18(4), С. 843 - 843

Опубликована: Апрель 17, 2017

There is highly credible evidence that melatonin mitigates cancer at the initiation, progression and metastasis phases. In many cases, molecular mechanisms underpinning these inhibitory actions have been proposed. What rather perplexing, however, large number of processes by which reportedly restrains development growth. These diverse suggest what being observed are merely epiphenomena an underlying more fundamental action remains to be disclosed. Some arresting on clearly membrane receptor-mediated while others receptor-independent involve direct intracellular this ubiquitously-distributed molecule. While emphasis melatonin/cancer research has role indoleamine in restraining breast cancer, changing quickly with types having shown susceptible inhibition melatonin. several facets could immediate applications clinical level. Many studies melatonin's co-administration improves sensitivity cancers conventional drugs. Even important findings renders previously totally resistant treatment sensitive same therapies. Melatonin also inhibits associated limiting entrance cells into vascular system preventing them from establishing secondary growths distant sites. This particular importance since often significantly contributes death patient. Another area deserves additional consideration related capacity reducing toxic consequences anti-cancer drugs increasing their efficacy. Although information available for than a decade, it not adequately exploited if only beneficial patients its ability attenuate acute long-term drug toxicity, should used improve physical wellbeing patients. The experimental findings, advantages using as co-treatment therapies would far exceed improvements

Язык: Английский

---

Melatonin treatment delays postharvest senescence and regulates reactive oxygen species metabolism in peach fruit

Postharvest Biology and Technology, Год журнала: 2016, Номер 118, С. 103 - 110

Опубликована: Апрель 14, 2016

Язык: Английский

---