Potential use of plants and their extracts in the treatment of coagulation disorders in COVID-19 disease: a narrative review

Coronavirus disease, i.e., COVID-19, is caused by the virus called “severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)”. Infection induces predominantly respiratory illness but is also associated with coagulation disorders which play an important role in the pathogenesis, clinical manifestations, and outcome of the disease. The treatment of hemostasis disorders of COVID-19 patients is a difficult problem to solve. For example, heparin is quite effective drug in reducing mortality in severe COVID-19 forms but not able to prevent venous and arterial thromboembolic complications. Moreover, anticoagulant therapy with heparin is associated with several adverse reactions, such as thrombocytopenia, osteoporosis, hypoaldosteronism and hypersensitivity reactions. New alternative anticoagulant molecules can be obtained from plants which are rich in polyphenols and flavonoids. These compounds, besides being potent antioxidants, also possess anti-inflammatory effect and, because able to inhibit the activity of many enzymes, including serine proteases, also anticoagulant properties. The purpose of this narrative review is to provide an overview of current literature data on coagulation disorders associated with COVID-19 disease and of the anticoagulant activity of plants and their extracts in order to evaluate their possible clinical application as alternative sources of novel molecules with anticoagulant and antithrombotic activity for the treatment of coagulation disorders in patients with COVID-19.