Grape Seed Extract inhibits norovirus

December 10, 2012

Norovirus is known as winter vomiting bug in England. In America it is commonly referred to as cruise ship virus. It causes more than half of all food-born illnesses in the United States, and is the second greatest source of reported food borne illness outbreaks in the European Union. Symptoms of the virus are nausea, vomiting and diarrhea.

Norovirus is transmitted mainly fecal-orally, and infected food handlers, contaminated water and surfaces are identified as important sources of transmission and a mere 10-100 virus particles are sufficient to transmit the disease. Norovirus can spread rapidly where crowds of people are packed together such as in college dorms, army bases and assisted living homes, or on cruise ships.

A recent study found that grape seed extract could reduce the infectivity of norovirus. The research was performed on norovirus surrogates. Dr. Dan Li of Ghent University in Belgium and collaborators has shown that grape seed extract works by denaturing the capsid protein, which is the coat of the virus, thereby disabling the virus.

In the study, the researchers observed that with exposure to grape seed extract, at low doses, the spherically-shaped murine (mouse) norovirus-1 coat proteins clumped, and showed "obvious deformation and inflation," according to the report. At higher doses, the researchers saw no coat proteins, only protein debris providing evidence that grape seed extract could effectively damage the norovirus capsid protein, which could reduce infectivity according to the report.

The researchers used surrogate viruses because there are no suitable animal models of norovirus, and human norovirus has been impossible to propagate in cell cultures. The surrogate virus, murine norovirus-1, can be grown in cell culture, and belongs to the same genus as human norovirus, and has a very similar genome structure, and morphology. Nonetheless and additionally, the researchers were able to measure the specific binding strength of human norovirus by two different methods, finding that it declined precipitously under the influence of grape seed extract, providing further support to their results. The research is published in the November 2012 issue of Applied and Environmental Microbiology.