Phytotherapic Drugs for COVID-19 Treatment: A Scoping Review

Background: The rapid eruption of Coronavirus at the end of 2019 has caused global health crisis and significant loss to the economy and social well-being. This created a massive shortage of advanced health facilities with inadequate medicinal supply, further deteriorating human health conditions. On the basis of adverse effects of the ongoing pandemic, this review has been proposed to evaluate the antiviral efficacy of plant- based therapeutics, against SARS-CoV-2 (commonly called COVID-19) infection. It highlights the possible action of the mechanism of phytotherapeutic drugs against coronavirus inhibition, further validated by clinical trials on herbal formulas is reviewed. Though the experimental studies on COVID-19 treatment are limited, the undesirable side effects of herbal drugs and unidentified compounds cannot be ignored. Objective: We have made an effort to study the prospective plant-derived bioactive entities and their effectiveness in the treatment of COVID-19 and also emphasize on safety and regulatory concerns of phytomedicines. Methods: The methodology involves relevant studies on COVID-19 treatment based on herbal extracts and the purified bioactive metabolites. The e-literature survey has been done by downloading research articles available on PubMed (National Library of medicine), Elsevier, and Google scholar search engines. The keywords used are plant metabolites, natural bioactive, phytotherapeutic drugs, clinical trials, SARS-CoV-2, Coronavirus inhibitors and herbal extracts. Results: The review pays particular attention to the etiological study of the COVID-19 virus and its inhibition using medicinal plant metabolites as immunomodulatory agents. The application of valuable bioactives like phenolic compounds, saponins, alkaloids, tannins, flavonoids and terpenoids in preparing herbal formula/drug has been focused on. The drug resistance of bioactive compounds and their side effects on human health were discussed for effective phytomedicine, thus, emphasizing the perspectives of phytotherapeutic drugs as a safe remedy to boost immunomodulatory functions and antiviral activity against COVID-19. Conclusion: Altogether, the review presents the action mechanism of plant extracts rich in bioactive compounds and depicted potential antiviral activity against SARS-CoV-2. These plant bioactive compounds can serve as lead molecules to develop phytomedicine, ensuring all safety regulations in the clinical trials to treat or prevent COVID-19 viral infections.