Immunomodulatory and Anti-Inflammatory Effects of Berberine in Lung Tissue and its Potential Application in Prophylaxis and Treatment of COVID-19

Natural products with known safety profiles are a promising source for the discovery of new drug leads. Berberine presents an example of one such phytochcmical that has been extensively studied for its anti-inflammatory and immunomodulatory properties against myriads of diseases, ranging from respiratory disorders to viral infections. A growing body of research supports the pluripotent therapeutic role berberine may play against the dreaded disease COVID-19. The exact pathophysiological features of COVID-19 are yet to be elucidated. However, compelling evidence suggests inflammation and immune dysregulations as major features of this disease. Being a potent immunomodulatory and anti-inflammatory agent, berberine may prove to be useful for the prevention and treatment of COVID-19. This review aims to revisit the pharmacological anti-inflammatory and immunomodulatory benefits of berberine on a multitude of respiratory infections, which like COVID-19, are known to adversely affect the airways and lungs. We speculate that berberine may help alleviate COVID-19 via preventing cytokine storm, restoring Th1/Th2 balance, and enhancing cell-mediated immunity. Furthermore, the role this promising phytochemical plays on other important inflammatory mediators involved in respiratory disorders will be underscored. We further highlight the role of berberine against COVID-19 by underscoring direct evidence from in silico, in vitro, and in vivo studies suggesting the inhibitory potential berberine may play against three critical SARS-CoV-2 targets, namely main protease, spike protein, and angiotensin-converting enzyme 2 receptor. Further preclinical and clinical trials are certainly required to further substantiate the efficacy and potency of berberine against COVID-19 in humans.