Antiviral Activities of Asarones and Rhizomes of <i>Acorus gramineus</i> on Murine Norovirus

Abstract

Noroviruses (NVs) are a major cause of foodborne diseases worldwide. The rhizomes of Acorus gramineus (AGR) have been used as a traditional medicinal plant and a food additive. In this study, AGR and its bioactive components—α-asarone and β-asarone—showed significant antiviral activities against murine NV (MNV) with pre-treatment, with more than two log reductions in viral plaques. They also demonstrated strong inhibition on binding to A- and O-type saliva by the recombinant P domain derived from human NV (HuNV) GII.4. Both α- and β-asarones also inhibited the binding of the P domain to the receptor at 0.125–1 mM in a concentration-dependent manner and induced a marked reduction in Tm, suggesting that they may reduce structural stability and block receptor binding by the P domain. In simulated digestive conditions, the AGR extract, α-asarone, or β-asarone further showed a significant reduction of MNV plaques by 1.5–2.8 logs. The asarones show a potential for development as a scaffold for anti-NV agents.

Keywords

• norovirus
• antiviral
• P domain
• <i>Acorus gramineus</i> rhizome
• asarone
• simulated digestive condition