Effects of Active Compounds of Nigella sativa in COVID-19: A Narrative Review

Abstract

Background: SARS-CoV-2 infection that led to the COVID-19 pandemic has changed human health and the economy globally. SARS-CoV-2 is a type of Coronaviruses that has caused pneumonia and its complications with many deaths over the past two years. The use of hydroxychloroquine and chloroquine, accepted as generally safe for patients with autoimmune diseases or malaria, was attempted in many trials for COVID-19 treatment. Nigella sativa (NS) (black caraway, also known as black cumin, Nigella or Kalonji) is an annual flowering plant of the Ranunculaceae family, chemically composed of the main constituent natural Thymoquinone (TQ) (30%-48%) in forms of thymohydroquinone, dithymoquinone (Nigellone) is a native to wider regions, including parts of eastern Europe, west Asia, North of Africa and east of Myanmar. In this review, we explored the Randomized Controlled Trial, Controlled Trial, and Systematic review studies that support Nigella sativa Thymoquinone-targeted SARS-CoV-2 targeting. Therefore, A literature search was performed for publications published on the electronic databases (PubMed, Embase, Scopus, CNKI, and Google Scholar) for Nigella sativa, black seeds, Kalonji, coronavirus, SARS-CoV-2 and COVID-19. This review aimed to find relevant evidence of Nigella sativa preferences as a natural feasible remedy with no side effects in COVID-19. Studies reported the benefits of NS as beneficial, another appropriate remedy for patients with COVID-19. However, all studies have shown limitations, such as limiting clinical symptom outcomes due to regulations imposed by isolation policies and lack of adequate funding. Therefore, the evidence suggests that the chemical contents of NS are a safe and possible treatment for COVID-19 patients that helps to improve COVID-19 infection in patients with no side effects. Conclusion: Nigella sativa seeds were one of the well-documented herbal products. Three reviewed randomized controlled trials reported that NS reduced COVID-19 risk and could improve immune function. It was also helpful in upper respiratory infections such as asthma and bronchitis, with one RCT showing that honey and NS significantly improved symptoms, viral clearance, and mortality of COVID-19 patients. This review concludes that NS has a positive barrier effect on people at risk of acquiring a COVID-19 infection.