Anti-influenza activity of berberine improves prognosis by reducing viral replication in mice.

Berberine, a natural isoquinoline alkaloid isolated from the berberis species, has a wide array of biological properties such as anti-inflammatory, antibacterial, antifungal, and antihelminthic effects. We evaluated the antiviral effect of berberine against influenza A/FM1/1/47 (H1N1) in vivo and in vitro. The results showed that berberine strongly suppressed viral replication in A549 cells and in mouse lungs. Meanwhile, berberine relieved pulmonary inflammation and reduced necrosis, inflammatory cell infiltration, and pulmonary edema induced by viral infection in mice when compared with vehicle-treated mice. Berberine suppressed the viral infection-induced up-regulation of TLR7 signaling pathway, such as TLR7, MyD88, and NF-κB (p65), at both the mRNA and protein levels. Furthermore, berberine significantly inhibited the viral infection-induced increase in Th1/Th2 and Th17/Treg ratios as well as the production of inflammatory cytokines. Our data provide new insight into the potential of berberine as a therapeutic agent for viral infection via its antiviral activity.