Melatonin as a complementary and prophylactic agent against COVID-19 in high-risk populations: A narrative review of recent findings from clinical and preclinical studies.

The coronavirus disease 2019 (COVID-19) pandemic has been going on around the world for more than a year and has cost a lot, as well as affected the quality of life of many. The psychological stress like delirium and sleep disturbances caused by the COVID-19 has affected many people in direct or indirect way by the disease. Insomnia and sleep deprivation have a negative effect on the immune system as well as disorders of the hormonal system, including the production and secretion of melatonin, known as the sleep hormone. Melatonin is a known anti-inflammatory and antioxidant agent in addition to its role in regulating circadian rhythms. In this review, we investigated the relationship between the effect of psychological stress caused by COVID-19 on patients, their families, health care workers, and occupations as well as how melatonin might act as a prophylactic agent with sedative effects and sleep enhancement potential. Search terms "melatonin" and "COVID-19" were manually searched on PubMed or other electronic database and relevant articles were included. Based on the review of scholarly articles, it can be inferred that melatonin, as an endogenous hormone controlling and regulating sleep and wakefulness in various researches, has a good potential due to its antioxidant and anti-inflammatory with minimal side effects. These beneficial effects highlight the impact of melatonin as an adjuvant and a potential alternative for the better management of SARS-CoV-2 infection in high-risk populations.

NLRP3 inflammasome activation and oxidative stress status in the mild and moderate SARS-CoV-2 infected patients: impact of melatonin as a medicinal supplement.

The inflammasome as a multiprotein complex has a role in activating ASC and caspase-1 resulting in activating IL-1ß in various infections and diseases like corona virus infection in various tissues. It was shown that these tissues are affected by COVID-19 patients. According to the current evidence, melatonin is not veridical while possessing a high safety profile, however, it possesses indirect anti-viral actions owing to its anti-oxidation, anti-inflammation, and immune improving properties. This study aims to assess the impacts of melatonin as the complementary treatments on oxidative stress agents and inflammasome activation in patients with COVID-19. Melatonin supplement (9 mg daily, orally) was provided for the patients hospitalized with a COVID-19 analysis for 14 days. For measuring IL-10, IL-1ß, and TNF-α cytokines and malondialdehyde (MDA), nitric oxide (NO), and superoxide dismutase (SOD) level and the expression of CASP1 and ASC genes, blood samples were gathered from the individuals at the start and termination of the therapy. Our findings indicated that melatonin is used as a complementary treatment to reduce the levels of TNF-α and IL-1ß cytokines, MDA, and NO levels in COVID-19 patients and significantly increase SOD level, however, the levels of IL-10 cytokine possesses no considerable changes. The findings revealed that genes of CASP1 and ASC were dysregulated by melatonin regulating the inflammasome complex. Based on the findings of the current study, it is found that melatonin can be effective as a medicinal supplement in decreasing the inflammasome multiprotein complex and oxidative stress along with beneficial impacts on lung cytokine storm of COVID-19 patients.

Evaluation of Th1 and Th2 mediated cellular and humoral immunity in patients with COVID-19 following the use of melatonin as an adjunctive treatment.

Coronavirus (SARS-CoV-2) is spreading rapidly in the world and is still taking a heavy toll. Studies show that cytokine storms and imbalances in T-helper (Th)1/Th2 play a significant role in most acute cases of the disease. A number of medications have been suggested to treat or control the disease but have been discontinued due to their side effects. Melatonin, as an intrinsic molecule, possesses pharmacological anti-inflammatory and antioxidant properties that decreases in concentration with age; as a result, older people are more prone to various diseases. In this study, patients who were hospitalized with a diagnosis of coronavirus disease 2019 (COVID-19) were given a melatonin adjuvant (9 mg daily, orally) for fourteen days. In order to measure markers of Th1 and Th2 inflammatory cytokines (such as interleukin (IL)-2, IL-4, and interferon (IFN)-γ) as well as the expression of Th1 and Th2 regulatory genes (signal transducer and activator of transcription (STAT)4, STAT6, GATA binding protein 3 (GATA3), and T-box expressed in T cell (T-bet)), blood samples were taken from patients at the beginning and end of the treatment. Adjuvant therapy with melatonin controlled and reduced inflammatory cytokines in patients with COVID-19. Melatonin also controlled and modulated the dysregulated genes that regulate the humoral and cellular immune systems mediated by Th1 and Th2. In this study, it was shown for the first time that melatonin can be used as a medicinal adjuvant with anti-inflammatory mechanism to reduce and control inflammatory cytokines by regulating the expression of Th1 and Th2 regulatory genes in patients with COVID-19.