Anti-coronaviral Activity of Plant and Seaweed Secondary Metabolites: A Review

Abstract

Background: The Coronavirus Disease 2019 (COVID-19), one of the greatest challenges facing humanity, continues to affect millions of people worldwide. Vaccines approved and authorized for use are effective against COVID-19, but viral variants of concern may emerge in the near future. The discovery of novel antiviral agents will help humanity overcome COVID-19 and aid in any future viral pandemics. Objective: This review aimed to evaluate evidence from the plant- and seaweed-derived secondary compound-based interventions for viral diseases caused by coronaviruses. Methods: A comprehensive search of several databases including Cochrane Library, Web of Science and PubMed were conducted to identify available studies evaluating the outcomes of plant- and seaweed secondary metabolites in viral diseases such as Severe Acute Respiratory Syndrome, Middle East Respiratory Syndrome and COVID-19. Results: The volume of existing reports is irrefutable evidence that some plant- and seaweed-derived secondary compounds (e.g., mannose-specific lectins, griffithsin, cyanovirin-N, gallate, curcumin, luteolin, quercetin and betulinic acid) possess a potential antiviral ability against coronaviruses, including SARS-CoV-2. Conclusion: Plant and seaweed secondary metabolites with antiviral activity show their activity in different metabolic pathways. Besides reducing and preventing the metabolic damage caused by proinflammatory cytokines and oxidative stress, several plant and seaweed secondary metabolites can also be effective in improving some clinical indexes specific to COVID-19. Despite their effectiveness in preclinical studies, plant and seaweed-derived secondary compounds need more pharmacokinetic studies and safety measures concerning their mitogenic and allergenic properties.