Epigallocatechin-3-gallate for COVID-19

This review discusses the prevention and treatment of coronavirus disease 2019 (COVID-19) caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Mutations in its spike glycoprotein have driven the emergence of variants with high transmissibility and immune escape capabilities. Some antiviral drugs are ineffective against the BA.2 subvariant at the authorized dose. Recently, 150 natural metabolites have been identified as potential candidates for development of new anti-COVID-19 drugs with higher efficacy and lower toxicity than those of existing therapeutic agents. Botanical drug-derived bioactive molecules have shown promise in dampening the COVID-19 cytokine storm and thus preventing pulmonary fibrosis, as they exert a strong binding affinity for viral proteins and inhibit their activity. The Health Ministry of Thailand has approved Andrographis paniculata (Jap. Senshinren) extracts to treat COVID-19. In China, over 85% of patients infected with SARS-CoV-2 receive treatments based on traditional Chinese medicine. A comprehensive map of the stages and pathogenetic mechanisms related to the disease and effective natural products to treat and prevent COVID-19 are presented. Approximately 10% of patients with COVID-19 are affected by long COVID, and COVID-19 infection impairs mitochondrial DNA. As the number of agents to treat COVID-19 is limited, adjuvant botanical drug treatments including vitamin C and E supplementation may reduce COVID-19 symptoms and inhibit progression to long COVID.

AbstractCOVID‐19, which was first identified in 2019 in Wuhan, China, is a respiratory illness caused by a virus called severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). Although some patients infected with COVID‐19 can remain asymptomatic, most experience a range of symptoms that can be mild to severe. Common symptoms include fever, cough, shortness of breath, fatigue, loss of taste or smell and muscle aches. In severe cases, complications can arise including pneumonia, acute respiratory distress syndrome, organ failure and even death, particularly in older adults or individuals with underlying health conditions. Treatments for COVID‐19 include remdesivir, which has been authorised for emergency use in some countries, and dexamethasone, a corticosteroid used to reduce inflammation in severe cases. Biological drugs including monoclonal antibodies, such as casirivimab and imdevimab, have also been authorised for emergency use in certain situations. While these treatments have improved the outcome for many patients, there is still an urgent need for new treatments. Medicinal plants have long served as a valuable source of new drug leads and may serve as a valuable resource in the development of COVID‐19 treatments due to their broad‐spectrum antiviral activity. To date, various medicinal plant extracts have been studied for their cellular and molecular interactions, with some demonstrating anti‐SARS‐CoV‐2 activity in vitro. This review explores the evaluation and potential therapeutic applications of these plants against SARS‐CoV‐2. This review summarises the latest evidence on the activity of different plant extracts and their isolated bioactive compounds against SARS‐CoV‐2, with a focus on the application of plant‐derived compounds in animal models and in human studies.

Natural products and plant extracts exhibit many biological activities, including that related to the defense mechanisms against parasites. Many studies have investigated the biological functions of secondary metabolites and reported evidence of antiviral activities. The pandemic emergencies have further increased the interest in finding antiviral agents, and efforts are oriented to investigate possible activities of secondary plant metabolites against human viruses and their potential application in treating or preventing SARS-CoV-2 infection. In this review, we performed a comprehensive analysis of studies through in silico and in vitro investigations, also including in vivo applications and clinical trials, to evaluate the state of knowledge on the antiviral activities of secondary metabolites against human viruses and their potential application in treating or preventing SARS-CoV-2 infection, with a particular focus on natural compounds present in food plants. Although some of the food plant secondary metabolites seem to be useful in the prevention and as a possible therapeutic management against SARS-CoV-2, up to now, no molecules can be used as a potential treatment for COVID-19; however, more research is needed.