Potential roles of phytochemicals in combating severe acute respiratory syndrome Coronavirus infection

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), the causative agent of the current ongoing global pandemic COVID-19 is yet far away from the clutches of contemporary western medicines. With the lack of conventional drugs for this deadly disease the scope for the development of herbal formulations and Ayurvedic medication is finding a sound basis in the current scenario. The past two years has witnessed detailed and focused investigations on the biologically active constituents derived from a range of medicinal plants and their potential antiviral properties against SARSCoV-2. The promising results of these investigations have intrigued the medical and plant experts in pharmacognosy enough to consider herbal medicines and plant-based products as they are more effective in combating the COVID-19 crisis. However, a large-scale application of the same would require more focused and thorough research on this matter. This review is an attempt to describe the current and future prospects of using medicinal plants and herbal compounds as natural and sustainable alternative for treating COVID-19. The current article evaluates the various strong evidences from biochemical and molecular studies that have been investigated so far for the development of herbal formulations to combat COVID-19 with detailed focus on the most potential phytochemicals of medicinal plants studied in this regard namely, Withania somnifera (L.) Dunal, Cinchona officinalis L., Curcuma longa L., Ocimum sanctum L., Azadirachta indica A. Juss. and Tinospora cordifolia (Willd.) Miers.