Pizza herb effective against Norovirus

The antiviral efficacy of oregano oil and its primary active component, carvacrol, would give another antimicrobial the opportunity to enter the internal part of the virus and kill it, said a study in the Journal of Applied Microbiology.

Norovirus, also known as the winter vomiting disease, is the leading cause of vomiting and diarrhoea worldwide.

The human form is nearly impossible to work on in the laboratory so researchers used the mouse form of the virus, which is considered the most similar in resistance to antimicrobials and disinfectants.

Food sanitizer use​

Dr Kelly Bright, who led the research at the University of Arizona, said: "Carvacrol could potentially be used as a food sanitizer and possibly as a surface sanitizer, particularly in conjunction with other antimicrobials. ​

“We have some work to do to assess its potential but carvacrol has a unique way of attacking the virus, which makes it an interesting prospect."​

Bright et al used murine norovirus (MNV) as a surrogate for human NoV to determine the antiviral efficacy of oregano oil and its primary active component, carvacrol.

Antiviral effect​

Oregano oil and carvacrol reduced MNV titres within 15 minutes of exposure. The infectivity of MNV treated with oregano oil remained stable but carvacrol produced more effective reductions within one hour of exposure.

Carvacrol appeared to act directly on the virus capsid – a tough layer of proteins that surrounds the virus – causing it to break down. This would give another antimicrobial the chance to enter the internal part of the virus and kill it.

“Both compounds appear to cause the viral capsid to lose its integrity, rather than merely inhibiting infectivity by binding to the capsid and preventing adsorption of the virus to host cells. This indicates that this is likely irreversible and thus true virus inactivation​,” said the researchers.

The virus may be transmitted through contaminated food or water, and inanimate surfaces.

Copper has also been shown to rapidly destroy the food poisoning bug, according to research from Southampton University​.

The study showed Norovirus was rapidly destroyed on copper and its alloys, with those containing more than 60% copper proving particularly effective.

Multiple experiments/assays were performed to determine the reason for the reductions in virus infectivity. These included a cell-binding assay, an RNase I protection assay and transmission electron microscopy (TEM) imaging.

Source: Journal of Applied Microbiology

Online ahead of print, DOI: 10.1111/jam.12453​

“​Antiviral efficacy and mechanisms of action of oregano essential oil and its primary component carvacrol against murine norovirus​”

Authors: D.H. Gilling, M. Kitajima, J.R. Torrey, K.R. Bright