scholarly journals Melatonin as an Add-On Treatment of COVID-19 Infection: Current Status

Diseases ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 64
Author(s):  
Gregory M. Brown ◽  
Seithikurippu R. Pandi-Perumal ◽  
Harold Pupko ◽  
James L. Kennedy ◽  
Daniel P. Cardinali

This brief review was written to provide a perspective on the flurry of reports suggesting that melatonin can be an important add-on therapy for COVID-19. Despite the passage of more than 60 years since its discovery and much evidence representing the contrary, there has been great reluctance to conceive melatonin as anything other than a hormone. Many other body chemicals are known to have multiple roles. Melatonin was first shown to be a hormone derived from the pineal gland, to be actively synthesized there only at night, and to act on targets directly or via the G-protein-coupled receptors (GPCRs) superfamily. It is of note that over 40 years ago, it was also established that melatonin is present, synthesized locally, and acts within the gastrointestinal tract. A wider distribution was then found, including the retina and multiple body tissues. In addition, melatonin is now known to have non-hormonal actions, acting as a free radical scavenger, an antioxidant, and as modulating immunity, dampening down innate tissue responses to invaders while boosting the production of antibodies against them. These actions make it a potentially excellent weapon against infection by the SARS-CoV-2 virus. Early published results support that thesis. Recently, a randomized controlled study reported that low doses of melatonin significantly improved symptoms in hospitalized COVID-19 patients, leading to more rapid discharge with no side effects, while significantly decreasing levels of CRP, proinflammatory cytokines, and modulating dysregulated genes governing cellular and humoral immunity. It is now critical that these trials be repeated, with dose-response studies conducted and safety proven. Numerous randomized controlled trials are ongoing, which should complete those objectives while also allowing for a more thorough evaluation of the mechanisms of action and possible applications to other severe diseases.

Antioxidants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 519 ◽  
Author(s):  
Costantino Paciolla ◽  
Stefania Fortunato ◽  
Nunzio Dipierro ◽  
Annalisa Paradiso ◽  
Silvana De Leonardis ◽  
...  

Vitamin C (l-ascorbic acid) is an excellent free radical scavenger, not only for its capability to donate reducing equivalents but also for the relative stability of the derived monodehydroascorbate radical. However, vitamin C is not only an antioxidant, since it is also a cofactor for numerous enzymes involved in plant and human metabolism. In humans, vitamin C takes part in various physiological processes, such as iron absorption, collagen synthesis, immune stimulation, and epigenetic regulation. Due to the functional loss of the gene coding for l-gulonolactone oxidase, humans cannot synthesize vitamin C; thus, they principally utilize plant-based foods for their needs. For this reason, increasing the vitamin C content of crops could have helpful effects on human health. To achieve this objective, exhaustive knowledge of the metabolism and functions of vitamin C in plants is needed. In this review, the multiple roles of vitamin C in plant physiology as well as the regulation of its content, through biosynthetic or recycling pathways, are analyzed. Finally, attention is paid to the strategies that have been used to increase the content of vitamin C in crops, emphasizing not only the improvement of nutritional value of the crops but also the acquisition of plant stress resistance.


Author(s):  
Paulina Iwan ◽  
Jan Stepniak ◽  
Malgorzata Karbownik-Lewinska

Abstract. Iodine is essential for thyroid hormone synthesis. Under normal iodine supply, calculated physiological iodine concentration in the thyroid is approx. 9 mM. Either potassium iodide (KI) or potassium iodate (KIO3) are used in iodine prophylaxis. KI is confirmed as absolutely safe. KIO3 possesses chemical properties suggesting its potential toxicity. Melatonin (N-acetyl-5-methoxytryptamine) is an effective antioxidant and free radical scavenger. Study aims: to evaluate potential protective effects of melatonin against oxidative damage to membrane lipids (lipid peroxidation, LPO) induced by KI or KIO3 in porcine thyroid. Homogenates of twenty four (24) thyroids were incubated in presence of either KI or KIO3 without/with melatonin (5 mM). As melatonin was not effective against KI-induced LPO, in the next step only KIO3 was used. Homogenates were incubated in presence of KIO3 (200; 100; 50; 25; 20; 15; 10; 7.5; 5.0; 2.5; 1.25 mM) without/with melatonin or 17ß-estradiol. Five experiments were performed with different concentrations of melatonin (5.0; 2.5; 1.25; 1.0; 0.625 mM) and one with 17ß-estradiol (1.0 mM). Malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA) concentration (LPO index) was measured spectrophotometrically. KIO3 increased LPO with the strongest damaging effect (MDA + 4-HDA level: ≈1.28 nmol/mg protein, p < 0.05) revealed at concentrations of around 15 mM, thus corresponding to physiological iodine concentrations in the thyroid. Melatonin reduced LPO (MDA + 4-HDA levels: from ≈0.97 to ≈0,76 and from ≈0,64 to ≈0,49 nmol/mg protein, p < 0.05) induced by KIO3 at concentrations of 10 mM or 7.5 mM. Conclusion: Melatonin can reduce very strong oxidative damage to membrane lipids caused by KIO3 used in doses resulting in physiological iodine concentrations in the thyroid.


2020 ◽  
Vol 35 (2) ◽  
pp. 212-219
Author(s):  
Rasmus Berggren ◽  
Jonna Nilsson ◽  
Yvonne Brehmer ◽  
Florian Schmiedek ◽  
Martin Lövdén

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