Plant-Derived Immunomodulators Targeting COVID-19 (SARS-CoV-2): Preclinical Evaluation and Clinical Trials

Abstract

Coronavirus disease-2019 (COVID-19) is a contagious disease that originated and proliferated via a novel viral strain named Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). Despite global exertions by the scientific community to comprehend it after its first emergence in December 2019, the pandemic warrants clinically proven prophylaxis and therapeutic strategies. Utilization of plant-derived immunomodulators to manage the current episode of coronavirus infection could set the instance signifying that traditional health care can contribute to treat the patients successfully. However, critical harnessing of all knowledge systems available worldwide would be a much preferred course of action. Some plants that are widely investigated for immunomodulating properties include Ocimum sanctum, Tinospora cordifolia, Withania somnifera, Glycyrrhiza glabra, and Emblica officinalis, which act as targets of COVID-19 highlighting their preclinical and clinical potential. These immunopotentiators and their constituents may be considered as potential adjuvant therapies to COVID-19 in clinics because of their action in numerous steps of the viral infection such as transmembrane protease serine 2 (TMPRSS2) inhibition and disruption of viral entry via binding to the viral fusion proteins and blocking angiotensin-converting enzyme-2 (ACE-2) receptor. The plant-derived bioactive immunomodulators provide sustenance to immunity and assist in combating SARS-CoV-2 by rejuvenating the human immune system. The chapter enlightens the beneficial properties of these phytoimmunomodulators to explore more evidences in combating COVID-19 via evaluation of preclinical and clinical trials.