Glycyrrhizin and glycyrrhetinic acid: pharmacological potential for the treatment of viral respiratory infections

Abstract

Glycyrrhizinic acid (also known as glycyrrhizin) (GA) and its derivative 18-β-Glycyrrhetinic acid (18b-GA), which are isolated from the plant Glycyrryza glabra, show several therapeutic properties, including antioxidant, anti-inflammatory, and antiviral activity. These are therefore being evaluated for several medical proposes, among them the treatment of respiratory infections induced by viruses. The current review aimed to highlight the potential of GA and 18b-GA as efficient drugs. Both molecules have demonstrated antiviral activity against SARS-CoV-2, due to different mechanisms; for instance, blocking key enzymes for virus entry to the cell or by limiting virus replication. Those properties are well known from in vitro and animal assay research, however, reports of their effects on humans are scarce. One of the main challenges of using GA and 18b-GA as a drug is improving their solubility and permeability, as well as using therapeutic doses without toxic effects. Due to the biological properties of GA and 18b-GA, the dose and administration type are crucial to achieving a high local concentration and therefore a therapeutic effect.