A recent study published in Scientific Reports has demonstrated the antiviral effectiveness of cetylpyridinium chloride against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Cetylpyridinium chloride is an ammonium compound commonly present in mouthwash.
Study: Antiviral effect of cetylpyridinium chloride in mouthwash on SARS-CoV-2. Image Credit: Latest Africa/Shutterstock
Background
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative pathogen of coronavirus disease 2019 (COVID-19) pandemic, is an enveloped, positive-sense, single-stranded RNA virus belonging to the human betacoronavirus family. The virus and its more aggressive variants have caused unprecedented damage to the worldwide healthcare system, with greater than 590 million confirmed infections and over 6.4 million deaths.
The first entry site of SARS-CoV-2 into the human body is the respiratory epithelium, which expresses high levels of the entry receptor angiotensin-converting enzyme 2 (ACE2). Evidence indicates that the virus can replicate within the oral cavity and release into saliva. The literature has also established an association between salivary content of SARS-CoV-2 and COVID-19 aggravation.
Considering the importance of oral hygiene within the context of SARS-CoV-2 infection, scientists in the present study have investigated the antiviral effect in addition to the mode of motion of cetylpyridinium chloride against SARS-CoV-2 infection.
Cetylpyridinium chloride is an antimicrobial compound widely utilized in mouthwash to forestall bacterial, fungal, or viral infections within the oral cavity. The compound is thought to exert antimicrobial effects by disrupting lipid membrane via physicochemical interactions. A number of studies have indicated that cetylpyridinium chloride is effective against wild-type SARS-CoV-2 at low concentrations (10–50 µg/ml).
Impact of cetylpyridinium chloride on SARS-CoV-2 infectivity
The study examined the antiviral effect of cetylpyridinium chloride on a variety of SARS-CoV-2 strains, including wild-type SARS-CoV-2 and alpha, beta, and gamma variants. The plaque assay was conducted to look at viral infectivity within the presence and absence of the compound.
The findings revealed that cetylpyridinium chloride at low concentrations (5 – 40 µg/ml) significantly suppresses the infectivity of all tested SARS-CoV-2 strains in a dose-dependent manner. The tested concentrations were lower than that utilized in commercially available mouthwash (50 µg/ml).
Impact of cetylpyridinium chloride on viral entry
The effect of cetylpyridinium chloride on viral entry was assessed by infecting ACE2-expressing cells with cetylpyridinium chloride-treated wild-type SARS-CoV-2.
The findings revealed that cetylpyridinium chloride significantly reduces the expression and duplicate variety of viral RNA in a dose-dependent manner. These findings indicate that cetylpyridinium chloride reduces the quantity of infectious virus before host cell entry.
Antiviral activity of cetylpyridinium chloride in saliva
Human saliva is extremely viscous and accommodates many proteins that will interfere with the antiviral efficacy of cetylpyridinium chloride. Saliva samples collected from healthy donors were mixed with the virus and cetylpyridinium chloride to find out the antiviral efficacy of the compound in saliva.
The findings revealed that cetylpyridinium chloride significantly suppresses viral infectivity even in saliva in a dose-dependent manner.
Antiviral mode of motion of cetylpyridinium chloride
Cetylpyridinium chloride-treated SARS-CoV-2 was subjected to sucrose density evaluation and transmission electron microscopy to find out the impact of cetylpyridinium chloride on viral morphology.
The findings revealed that cetylpyridinium chloride doesn’t impact the general structure of the virus. The spherical particle structure of SARS-CoV-2 remained unchanged after cetylpyridinium chloride treatment.
Study significance
The study highlights the potency of cetylpyridinium chloride in inhibiting SARS-CoV-2 and its variants even at low concentrations. The antiviral activity of the compound stays unchanged in human saliva.
The study has tested the antiviral efficacy of a business mouthwash that accommodates the same concentration of cetylpyridinium chloride as utilized in the study. The mouthwash exhibits similar and even higher antiviral efficacy than pure cetylpyridinium chloride solution. This means that the opposite ingredients present within the mouthwash don’t interfere with the anti-SARS-CoV-2 activity of cetylpyridinium chloride.
Regarding mode of motion, the study suggests that cetylpyridinium chloride exerts anti-SARS-CoV-2 activity likely by denaturing viral proteins and never by disrupting lipid membrane.
Overall, the study indicates that cetylpyridinium chloride-containing products will be used as a safety measure to scale back the transmission rate and progression of SARS-CoV-2 infection.
An ongoing clinical study is examining the effect of cetylpyridinium chloride on SARS-CoV-2 viral load within the saliva of COVID-19 patients.