Melatonin as a potential therapeutic molecule against COVID-19 associated gastrointestinal complications: An unrevealed link

Abstract

Outbreak of the novel coronavirus disease (COVID-19) was first reported in Wuhan, Hubei province of China, in early December 2019 which was later declared as a pandemic by World Health Organization (WHO) in March 2020. The International Committee on Taxonomy of Viruses has termed this novel coronavirus as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). According to the report of WHO on 29th April, 2020, 3018681 confirmed cases along with 207973 deaths have been documented globally. COVID-19 was originally reported as a lethal lung disease with fever and cough as the most common symptoms; however, the increasing number of gastrointestinal symptoms, such as diarrhoea, vomiting and abdominal pain in patients have clearly suggested that gastrointestinal tract (GIT) may also serve as a potential route for SARS-CoV-2 infection. To identify the effective therapies on this pandemic is urgent. Keeping this in mind, we realize that melatonin is a potent antioxidant, anti-inflammatory and immunomodulatory molecule and it has been used in diverse diseases and pathophysiological conditions, including respiratory disease and viral infections. Importantly, melatonin specific receptors and its endogenously synthetic machinery are distributed throughout the mammalian gastrointestinal system. Therefore, the therapeutic potentiality of melatonin in SARS-CoV-2 associated digestive symptoms cannot be ignored. In this review, we focus on the clinical implications of melatonin on the digestive complications associated with SARS-CoV-2 infection.