Herbal Medicines to Fight Against COVID-19: New Battle with an Old Weapon

The world population has suffered as a result of the COVID-19 pandemic. The disease has become life-threatening in a very short time, harming citizens and the economic systems globally. The novel virus SARS-CoV-2 has been known as the causative agent of COVID-19. The SARS-CoV-2 is a single-stranded RNA virus having ~30 kb genomic components, which are 70% identical to SARS-CoV. The main process of the pathophysiology of COVID-19 has been associated with the interaction of a novel coronavirus with host cell receptor, angiotensin-converting enzyme-2 (ACE 2), by fusion. Therapeutic agents having serine protease inhibitors and ACE-2 blockers may be explored for the treatment by inhibiting the viral target such as Mpro, RdRp, PLpro, and helicase. Herbal medicine has a wide array of chemical entities with potential health benefits, including antiviral activity, which may be explored as an alternative treatment for COVID-19. The herbal bioactives like catechins, andrographolide, hesperidin, biorobin, scutellarein, silvestrol, shikonin, tryptanthrin, vitexin quercetin, myricetin, caffeic acid, psoralidin, luteolin, etc. have shown potential inhibitory effect against SARS-CoV-2. Recent research reports indicate that the various plant secondary metabolites have shown potential antiviral activities. The present review article highlights the recent information on the mechanism of actions and applications of herbal medicine in the treatment of COVID-19.