Rosmarinic acid interferes with influenza virus A entry and replication by decreasing GSK3ß and phosphorylated AKT expression levels.

ABSTRACT

BACKGROUND: The purpose of this study was to examine the in vivo activity of rosmarinic acid (RA) - a phytochemical with antioxidant, anti-inflammatory, and antiviral properties - against influenza virus (IAV). An antibody-based kinase array and different in vitro functional assays were also applied to identify the mechanistic underpinnings by which RA may exert its anti-IAV activity. METHODS: We initially examined the potential efficacy of RA using an in vivo mouse model. A time-of-addition assay and an antibody-based kinase array were subsequently applied to investigate mechanism-of-action targets for RA. The hemagglutination inhibition assay, neuraminidase inhibition assay, and cellular entry assay were also performed. RESULTS: RA increased survival and prevented body weight loss in IAV-infected mice. In vitro experiments revealed that RA inhibited different IAV viruses - including oseltamivir-resistant strains. From a mechanistic point of view, RA downregulated the GSK3ß and Akt signaling pathways - which are known to facilitate IAV entry and replication into host cells. CONCLUSIONS: RA has promising preclinical efficacy against IAV, primarily by interfering with the GSK3ß and Akt signaling pathways.