The natural polyphenol proanthocyanidin A2 prevents the in vitro infection of Ebola virus and rabies virus by interfering with the early phases of the replication cycle

Ebola virus and Rabies virus are enveloped viruses that cause lethal zoonoses with very high fatality rates. Proanthocyanidin A2 (PAC-A2) is a compound in cranberry extract reported to possess antiviral properties thus it is viewed as a potential broad-spectrum antiviral agent. In this study the PAC-A2 was assessed for effectiveness and mechanism of action against Ebola virus and Rabies virus. In cell cultures, pseudoviruses of Ebola and Rabies, and subsequently authentic viruses were evaluated using mode of action assays. These showed that inhibition occurs during the early stages of the viral life cycle, specifically during attachment and entry into host cells. Biochemical assays such as electrophoresis and fluorescence spectroscopy indicated direct interactions between the PAC-A2 and the envelope glycoproteins of Ebola virus and Rabies virus. These results propose  PAC-A2 is a potential plant-based broad-spectrum antiviral but further studies, such as using in vivo systems and evaluation using non-enveloped viruses are required to support this claim.
(SWM)