Potential of herbal products in prevention and treatment of COVID-19. Literature review

The COVID-19 epidemic is the greatest pandemic that human kind experienced for decades, with high morbidity and mortality. Despite recent development of vaccines there is still many severe cases of COVID-19. Unfortunately there is still no standardized therapies and treatment of severe cases is very challenging. The aim of this study is to indicate if herbs administered alone or as a complementary therapy could be used as prophylaxis or treatment of SARS-CoV-2 infection. Over 85% of patients with COVID-19 in China used Traditional Chinese Medicine (TCM), and a most common herb is Glycyrrhiza glabra, which in vitro inhibits replication of different enveloped viruses, including coronaviruses. Glycyrrhizin in vitro connects and changes conformation of ACE2 receptors, which are vital for SARS-CoV-2 penetration into host cells. Pelargonium sidoides show immunomodulatory and antiviral properties in clinical and in vitro studies, and it inhibits replication of HCo-229E coronavirus. Glycyrrhiza glabra in combination with standard therapies significantly reduces the hospitalization rate and occurrence of COVID-19 symptoms. As complementary therapies lianhuaqingwen capsules and jinhua qinggan granules reduces hospitalization rates, time to symptoms recovery and improve patient psychological comfort. In view of SARS-CoV-2 other herbs are not effective, e.g. maxingshigan–yinqiaosan, or therapeutic concentration would be impossible to achieve, e.g. ephedra herb, or there is simply no proper data. Therefore, Liquorice and Pelargonium sidoides are effective against coronaviruses and could be possibly used as prophylaxis and treatment of COVID-19, while lianhuaqingwen capsules and jinhua qinggan granules can be useful as a complementary therapy to conventional treatment.