Zeylanone epoxide isolated from Diospyros anisandra stem bark inhibits influenza virus in vitro.

Influenza virus infection is a public health problem, causing significant morbidity and mortality. Currently, zanamivir and oseltamivir are in common use, and there are already reports of antiviral resistance. Several studies have shown the antiviral potential of a wide variety of plant-based natural compounds, among them those of the quinone type. In this study, we evaluated the antiviral activity of naphthoquinones isolated from the stem bark of Diospyros anisandra, and we selected zeylanone epoxide (ZEP) to study its effects on influenza A and B viruses. Our results indicated that ZEP inhibits the replication of influenza A and B viruses, at early and middle stages of the replication cycle. Confined nuclear localization of the viral NP indicated that ZEP affects its intracellular distribution and reduces viral yield. This is the first report on the antiviral properties and possible mechanism of action of ZEP in vitro, showing its broad-spectrum activity against influenza A and B viruses.