The inhibitory effects of toothpaste and mouthwash ingredients on the interaction between the SARS-CoV-2 spike protein and ACE2, and the protease activity of TMPRSS2 in vitro

Investigation of the constituents of commercially available toothpastes

OBJECTIVES

Toothpaste plays a pivotal role in oral and dental hygiene. This cross-sectional study not only investigates the constituents of toothpastes available in the market and their frequency across different brands but also delves into the potential side effects, irritations, or unfavourable outcomes of these constituents, emphasizing the broader health and environmental implications.

METHODS

The largest of the five major chain markets in each district of Istanbul was visited, and adult toothpastes were included in this study. All the constituents that make up the toothpaste were individually recorded in an Excel database. Subsequently, literature regarding the purposes, toxic and potential side effects of each ingredient was gathered using databases such as Google Scholar, PubMed and ScienceDirect. The percentages of these ingredients' occurrence among all the toothpastes were calculated, and the ingredients were categorized into 15 distinct groups based on their usage purposes.

RESULTS

There were 160 different varieties of toothpaste belonging to 19 different brands on the market shelves. Although a total of 244 different ingredients were identified, only 78 of them were included in the study. Among the analysed toothpaste types, 105 of them were found to contain 1450 ppm fluoride, whilst 26 toothpaste variants were discovered to have fluoride levels below this value. Among the various ingredients analysed, particular attention was drawn to commonly debated compounds in oral care products. Specifically, titanium dioxide was found in 68% (n = 111) of the varieties, sodium lauryl sulphate in 67% (n = 108) and paraben in 2% (n = 4), respectively.

CONCLUSION

Whilst certain ingredients may raise concerns for potential side effects and health considerations within the human body, the toothpaste has long been regarded as an indispensable tool for maintaining optimal oral and dental health. However, gaining a deeper understanding and conducting research on each constituent that comprises the toothpaste, as well as raising awareness in this regard, holds significant importance for human health.

Ingredients in Commercially Available Mouthwashes

OBJECTIVES

Mouthwashes, a cornerstone of oral and dental hygiene, play a pivotal role in combating the formation of dental plaque, a leading cause of periodontal disease and dental caries. This study aimed to review the composition of mouthwashes found on retail shelves in Turkey and evaluate their prevalence and side effects, if any.

METHODS

The mouthwashes examined were sourced from the 5 largest chain stores in each district of Istanbul. A comprehensive list of the constituents was meticulously recorded. The research was supported by an extensive compilation of references from scholarly databases such as Google Scholar, PubMed, and ScienceDirect. Through rigorous analysis, the relative proportions of mouthwash ingredients and components were determined.

RESULTS

A total of 45 distinctive variations of mouthwashes, representing 17 prominent brands, were identified. Amongst the 116 ingredients discovered, 70 were evaluated for potential adverse effects and undesirable side effects. The aroma of the mouthwash (n = 45; 100%), as welll as their sodium fluoride (n = 28; 62.22%), sodium saccharin (n = 29; 64.44%), sorbitol (n = 21; 46.6%), and propylene glycol (n = 28; 62.22%) content were the main undesireable features.

CONCLUSIONS

The limited array of mouthwashes found on store shelves poses a concern for both oral and public health. Furthermore, the intricate composition of these products, consisting of numerous ingredients with the potential for adverse effects, warrants serious attention. Both clinicians and patients should acknowledge the importance and unwarranted side effects of the compnents of the mouthwashes.

Efficacy of different mouthwashes against COVID-19: A systematic review and network meta-analysis

To evaluate the effectiveness of antiseptic mouthwashes in reducing SARS-CoV-2 load clinically and in vitro. A systematic electronic search (MEDLINE/Scopus/Cochrane) was conducted to identify prospective clinical and in vitro studies published between 2019 included and 16 June 2023 assessing the effectiveness of mouthwashes in reducing SARS-CoV-2 load in saliva or surrogates. Data were summarized in tables and a network meta-analysis was performed for clinical trials. Thirty-five studies (14 RCTs, 21 in vitro) fulfilled the inclusion criteria. The risk of bias was judged to be high for 2 clinical and 7 in vitro studies. The most commonly test product was chlorhexidine alone or in combination with other active ingredients, followed by povidone-iodine, hydrogen peroxide and cetylpyridinium chloride. Overall, the descriptive analysis revealed the effectiveness of the mouthwashes in decreasing the salivary viral load both clinically and in vitro. Network meta-analysis demonstrated a high degree of heterogeneity. Among these studies, only chlorhexidine 0.20% was associated to a significant Ct increase in the saliva 5 min after rinsing compared to non-active control (p = 0.027). Data from clinical and in vitro studies suggested the antiviral efficacy of commonly used mouthwashes. Large well-balanced trials are needed to identify the best rinsing protocols.

Combined copper and zinc deficiency is associated with reduced SARS-CoV-2 immunization response to BNT162b2 vaccination

The essential trace elements copper, selenium and zinc are of relevance for immunity and immune response to vaccination. In this longitudinal study, adult healthcare workers (n = 126) received two doses of an mRNA vaccine (BNT162b2), and longitudinal serum samples were prepared. Vaccine-induced antibodies and their neutralizing activity were analyzed, and the trace elements copper, zinc, and selenium along with the copper transporter ceruloplasmin were measured. Subjects with combined deficiency of copper and zinc, i.e. both in the lowest tertiles at baseline, displayed particularly low antibody titers at three (Double Q1: 13 AU/mL vs. not double Q1: 29 AU/mL) and six (Double Q1: 200 AU/mL vs. not double Q1: 425 AU/mL) weeks after vaccination (p < 0.05). The results indicate the potential importance of an adequate trace element status of copper and zinc for raising a strong vaccine-induced SARS-CoV-2 antibody response, and highlights the importance of considering combined micronutrient insufficiencies, as single deficiencies may synergize.

Cuprous oxide nanoparticles incorporated into a polymeric matrix embedded in fabrics to prevent spread of SARS-CoV-2

This paper describes the development of a coating for cotton and polypropylene (PP) fabrics based on a polymeric matrix embedded with cuprous oxide nanoparticles (Cu₂O@SDS NPs) in order to inactivate SARS-CoV-2 and manufactured by a simple process using a dip-assisted layer-by-layer technology, at low curing temperature and without the need for expensive equipment, capable of achieving disinfection rates of up to 99%. The polymeric bilayer coating makes the surface of the fabrics hydrophilic, enabling the transportation of the virus-infected droplets to achieve the rapid inactivation of SARS-CoV-2 by contact with the Cu₂O@SDS NPs incorporated in the coated fabrics.

Efficacy of Mouth Rinses and Nasal Spray in the Inactivation of SARS-CoV-2: A Systematic Review and Meta-Analysis of In Vitro and In Vivo Studies

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) is a global and evolving pandemic associated with heavy health and financial burdens. Considering the oral cavity as the major reservoir for SARS-CoV-2, a systematic review and meta-analysis were conducted to assess the efficacy of mouth rinses and nasal sprays in reducing the salivary viral load of SARS-CoV-2. All in vivo and in vitro studies that assessed the virucidal efficacy of mouth rinses and nasal sprays against SARS-CoV-2 and were published in the English language from December 2019 to April 2022 were considered for analyses. Special Medical Subject Headings terms were used to search Pubmed, Scopus, Embase Ovid, and Web of Science databases. The toxicological data reliability assessment tool (ToxRToool) was used to assess the quality of the included studies. Thirty-three studies (11 in vivo and 22 in vitro) were deemed eligible for inclusion in this analysis. Results of the pooled data showed that povidone-iodine is the most efficacious intervention in vivo in terms of reducing the SARS-CoV-2 salivary viral load, followed by chlorhexidine. The mean difference in the viral load was 86% and 72%, respectively. Similarly, povidone-iodine was associated with the highest log₁₀ reduction value (LRV) in vitro, followed by cetylpyridinium chloride, (LRV = 2.938 (p < 0.0005) and LRV = 2.907 (p = 0.009), respectively). Povidone-iodine-based oral and nasal preparations showed favourable results in terms of reducing SARS-CoV-2 viral loads both in vivo and in vitro. Considering the limited number of patients in vivo, further studies among larger cohorts are recommended.

Virtual Screening and Quantum Chemistry Analysis for SARS-CoV-2 RNA-Dependent RNA Polymerase Using the ChEMBL Database: Reproduction of the Remdesivir-RTP and Favipiravir-RTP Binding Modes Obtained from Cryo-EM Experiments with High Binding Affinity

The novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was identified as the pathogenic cause of coronavirus disease 2019 (COVID-19). The RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 is a potential target for the treatment of COVID-19. An RdRp complex:dsRNA structure suitable for docking simulations was prepared using a cryo-electron microscopy (cryo-EM) structure (PDB ID: 7AAP; resolution, 2.60 Å) that was reported recently. Structural refinement was performed using energy calculations. Structure-based virtual screening was performed using the ChEMBL database. Through 1,838,257 screenings, 249 drugs (37 approved, 93 clinical, and 119 preclinical drugs) were predicted to exhibit a high binding affinity for the RdRp complex:dsRNA. Nine nucleoside triphosphate analogs with anti-viral activity were included among these hit drugs, and among them, remdesivir-ribonucleoside triphosphate and favipiravir-ribonucleoside triphosphate adopted a similar docking mode as that observed in the cryo-EM structure. Additional docking simulations for the predicted compounds with high binding affinity for the RdRp complex:dsRNA suggested that 184 bioactive compounds could be anti-SARS-CoV-2 drug candidates. The hit bioactive compounds mainly consisted of a typical noncovalent major groove binder for dsRNA. Three-layer ONIOM (MP2/6-31G:AM1:AMBER) geometry optimization calculations and frequency analyses (MP2/6-31G:AMBER) were performed to estimate the binding free energy of a representative bioactive compound obtained from the docking simulation, and the fragment molecular orbital calculation at the MP2/6-31G level of theory was subsequently performed for analyzing the detailed interactions. The procedure used in this study represents a possible strategy for discovering anti-SARS-CoV-2 drugs from drug libraries that could significantly shorten the clinical development period for drug repositioning.

Covid-19 and SARS-CoV-2 infection in periodontology: A narrative review

The present review examined the available evidence on possible involvement of gingival tissues in SARS‐CoV‐2 infection. Gingival tissue possess SARS‐CoV‐2 entry and transmission factors, among them ACE2 (angiotensin‐converting enzyme 2) and TMPRSS2 (transmembrane protease serine 2), which are the principal mediators of the virus cell invasion. Clinical observations reveal SARS‐CoV‐2 RNA in periodontal tissues and crevicular fluid, suggesting that the periodontium may act as an entry point for the virus and/or as a dissemination site. The preliminary observations prove infection potential of gingival crevicular fluid and shed epithelial cells from the periodontium. There are also findings on potential associations between periodontitis and Covid‐19 (coronavirus disease 2019). PubMed and Scopus databases were used to search for suitable keywords such as: SARS‐CoV‐2, Covid‐19, oral virus infection, gingival crevicular fluid, oral mucosa, periodontium, gingiva, ACE2, TMPRSS2, Furin, diagnosis, topical treatment, vaccine and the related words for relevant publications. Data extraction and quality valuation of articles were performed by the author. The review addressed seven major domains: periodontal structures as SARS‐CoV‐2 infection site, the periodontal changes under SARS‐CoV‐2 infection, potential associations between periodontitis and Covid‐19, periodontal oral care in Covid‐19, crevicular fluid as potential transmission factor and preventive measures. The search process in PubMed and Scopus was updated up to 31 March 2022. Finally 68 articles were retrieved for the final analysis, from the initial database searches. According to the inclusion criteria articles in English language without any date restriction were included. The included studies were mostly original articles, and published in 2020 and 2021 with the aim to describe Covid‐19 and SARS‐CoV‐2 infection in periodontology. As a conclusion it can be stated that gingival tissues may play a role in SARS‐CoV‐2 infection.

In vitro virucidal activity of mouthwashes on SARS‐CoV‐2

Objectives

Materials and Methods

Results

Conclusions

Relationship between Toothpaste Dilution Ratio and Droplets Generated during Tooth-Brushing

Guidelines for using toothpaste during tooth-brushing in public places during the coronavirus epidemic are lacking. In addition, the advantages and disadvantages of using toothpaste in terms of droplet generation during brushing, the number of droplets generated, and their scatter range are unknown; therefore, we investigated the relationships between diluted toothpaste viscosity, the number of droplets generated, and the droplets’ flight distance. We developed a system to quantitate droplet generation during tooth-brushing. Brushing with water generated 5965 ± 266 droplets; 10.0× diluted toothpaste generated 538 ± 56, 4.00× diluted toothpaste generated 349 ± 15, and 2.00× diluted toothpaste generated 69 ± 27 droplets. Undiluted toothpaste generated no droplets. Droplet number tended to increase with increased toothpaste dilution ratio and decreased viscosity (r = −0.993). The maximum flight distances were 429 ± 11, 445 ± 65, 316 ± 38, and 231 ± 21 mm for water, 10.0×, 4.00×, and 2.00× diluted toothpaste, respectively. The maximum flight distance and toothpaste viscosity correlated negatively (r = −0.999). Thus, the less diluted the toothpaste, the fewer the droplets generated during brushing, and the shorter their flight distance. The use of an appropriate amount of toothpaste is recommended to prevent droplet infection during tooth-brushing.

Oral Pathology in COVID-19 and SARS-CoV-2 Infection-Molecular Aspects

This review article was designed to evaluate the existing evidence related to the molecular processes of SARS-CoV-2 infection in the oral cavity. The World Health Organization stated that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and transmission is produced by respiratory droplets and aerosols from the oral cavity of infected patients. The oral cavity structures, keratinized and non-keratinized mucosa, and salivary glands' epithelia express SARS-CoV-2 entry and transmission factors, especially angiotensin converting enzyme Type 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2). Replication of the virus in cells leads to local and systemic infection spread, and cellular damage is associated with clinical signs and symptoms of the disease in the oral cavity. Saliva, both the cellular and acellular fractions, holds the virus particles and contributes to COVID-19 transmission. The review also presents information about the factors modifying SARS-CoV-2 infection potential and possible local pharmacotherapeutic interventions, which may confine SARS-CoV-2 virus entry and transmission in the oral cavity. The PubMed and Scopus databases were used to search for suitable keywords such as: SARS-CoV-2, COVID-19, oral virus infection, saliva, crevicular fluid, salivary gland, tongue, oral mucosa, periodontium, gingiva, dental pulp, ACE2, TMPRSS2, Furin, diagnosis, topical treatment, vaccine and related words in relevant publications up to 28 December 2021. Data extraction and quality evaluation of the articles were performed by two reviewers, and 63 articles were included in the final review.

Computational screening of camostat and related compounds against human TMPRSS2: A Potential Treatment of COVID-19

The global coronavirus pandemic has burdened the human population with mass fatalities and disastrous socio-economic consequences. The frequent occurrence of these new variants has fueled the already prevailing challenge. There is still a necessity for highly effective small molecular agents to prevent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Here, we targeted the human transmembrane surface protease TMPRSS2, which is essential for proteolytic activation of SARS-CoV-2. Camostat is a well-known inhibitor of serine proteases and an effective TMPRSS2 inhibitor. A virtual library of camostat-like compounds was computationally screened against the catalytic site of TMPRSS2. Following a sequential in-depth molecular docking and dynamics simulation, we report the compounds that exhibited promising efficacy against TMPRSS2. The molecular docking and MM/PBSA free energy calculation study indicates these compounds carry excellent binding affinity against TMPRSS2 and found them more effective than camostat. The study will open doors for the effective treatment of coronavirus disease 2019.