Suppression of porcine reproductive and respiratory syndrome virus proliferation by glycyrrhizin

Glycyrrhizin is a natural component extracted from the roots of Glycyrrhiza glabra. In this study, we investigated the antiviral activity of glycyrrhizin against porcine reproductive and respiratory syndrome virus (PRRSV), an Arterivirus that has been devastating the swine industry worldwide since the late 1980s. Our results showed that treatment with glycyrrhizin significantly reduced PRRSV proliferation and PRRSV-encoded protein expression in a dose-dependent manner. Mechanistically, glycyrrhizin mainly inhibits the penetration stage, and has little effect on the steps of adsorption or release of PRRSV in its life cycle. Furthermore, we were able to exclude a direct inhibitory action of glycyrrhizin on PRRSV particles. Given these results, glycyrrhizin may be a candidate component for a novel porcine reproductive and respiratory syndrome (PRRS) control strategy.