Xylitol and grapefruit seed extract shows promise in preventing SARS-CoV-2 infection, study finds

The coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has wreaked havoc worldwide. It has spread since its first emergence in December 2019, reaching 191 countries and territories.

The vast spread of the virus has warranted scientists and pharmaceutical companies to develop drugs and vaccines. Some resorted to repurposing drugs, which have been approved safe and effective by regulatory agencies for other diseases. These can be used to treat COVID-19 patients.

A team of researchers in the US have demonstrated that xylitol and grapefruit seed extract (GSE) could potentially prevent SARS-CoV-2 infection. These can be used as a nasal spray to contain the spread of the coronavirus.

COVID-19 pandemic

Like other viral pandemics that ravaged across the globe, the coronavirus pandemic has taken a toll on most affected countries. Lockdowns have closed schools and businesses for many months. Up to date, there are more than 67 million people have been infected, and the virus has claimed over 1.53 million lives.

The societal cost of COVID-19 is challenging to measure, but millions of people have lost their livelihoods. Until a vaccine or cure is approved, the world may need to tailor policies to prevent virus spread.

Aside from vaccines and drugs, scientists are also looking into prophylactic methods to prevent infection with SARS-Cov-2.

What is xylitol?

Xylitol is a naturally occurring alcohol found in most plant material such as fruits and vegetables. It is widely used as a sugar substitute in "sugar-free" candies, mints, and chewing gums.

Past studies have demonstrated the anti-viral properties of polyols. For instance, xylitol has been reported to reduce the severity of viral infections. In mouse models, dietary xylitol's effect on the human respiratory syncytial virus, which affects the respiratory tract, was noted, showing promising results. The mice that received xylitol for 14 days before virus exposure had reduced viral lung titers than the control.

Xylitol also shows promise in preventing bacterial infections. It can reduce the levels of harmful bacteria in the oral cavity by 27 to 75 percent.

Xylitol has a long history of being safe and beneficial in preventing bacterial infections. It is also considered a prebiotic due to its positive effect on the microbiome, reducing the risk of pathogenic proliferation.

The study

The study, published in the pre-print journal bioRxiv, highlights xylitol's efficacy on the SARS-CoV-2 and other viral infections that affect the respiratory tract.

The team formulated a nasal spray containing xylitol, grapefruit seed extract, and saline solution to arrive at the study findings. The team tested the nasal spray on virus titers of SARS-CoV-2.

The researchers observed for toxicity and found that after a 25-minute contact time, the nasal spray reduced the virus from 4.2 to 1.7 log10 CCID50 per 0.1 ml, a statistically significant reduction.

Upon checking the STEM images obtained at the BIoCryo Laboratory (Northwestern University), these revealed that the virus was contained on the cell wall but none intra-cellular, possibly due to D-xylose (xylitol) production glycoaminoglycans decoy targets.

"Combination therapy with GSE and xylitol may prevent the spread of viral respiratory infections not just for SAR-CoV-2 but also for future H1N1 or other viral epidemics," the team concluded.

"GSE significantly reduces the viral load while xylitol prevents the virus attachment to the core protein on the cell wall," they added.

The team concluded that xylitol and grapefruit seed extract are expensive or rare, making them good agents to control viral outbreaks. When formulated as a nasal spray, it can prevent infection with SARS-CoV-2 and other respiratory viruses.

The spray will also allow for comfortable long-term mask-wearing amid the coronavirus pandemic.

"Because there are no risk factors in using the xylitol and GSE combination therapy, and the nasal spray is over the counter available without a prescription, and the spray allows for comfortable long term mask-wearing, adoption of this preventive anti-viral therapy should be encouraged," they added.

*Important Notice

bioRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:
Angela Betsaida B. Laguipo

Written by

Angela Betsaida B. Laguipo

Angela is a nurse by profession and a writer by heart. She graduated with honors (Cum Laude) for her Bachelor of Nursing degree at the University of Baguio, Philippines. She is currently completing her Master's Degree where she specialized in Maternal and Child Nursing and worked as a clinical instructor and educator in the School of Nursing at the University of Baguio.


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  1. dsddy J dsddy J United States says:

    Cannon, M., Westover, J., Bleher, R., Sanchez-Gonzales, M., and Ferrer, G. (2020). In Vitro Analysis of the Anti-viral Potential of nasal spray constituents against SARS-CoV-2.

    The "research" is poorly designed, poorly communicated, and lacks any evidence supporting anything useful.  The methods section is so poorly written as to be almost impossible to  replicate.  This "research" and the supposed benefits lacks any support from a properly designed and executed study.
    At best, it is an extremely early initial experiment that may suggest further investigation, but is not sufficient at this mment to warrant publication by any credible journal.

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