(P20-041-23) Bioactive Mouth Rinse Containing Inorganic Nitrates and Antioxidants Modulates the Oral Microbiome in Support of the Enterosalivary Pathway

Objectives: The oral microbiome is highly variable and influences the efficiency of nitrate reduction by the enterosalivary pathway and, consequently, vascular health. This study investigated the oral microbial changes that ensue following use of a mouth rinse infused with inorganic nitrate and antioxidants over a one-week period compared to a standard antibacterial mouth rinse with chlorhexidine (CHX).

Methods: Nine-week old male Wistar rats (n=20) were randomized to the bioactive mouth rinse group containing nitrate or standard antibacterial mouth rinse with 0.02% CHX. The bioactive rinse was comprised of a 5% green tea base with added nitrate and antioxidants (vitamin C). The assigned rinse was administered twice daily for one week. The dorsal tongue of each rat was sampled with a sterile swab at baseline and completion. Oral microbiome was assessed by 16S rRNA V4 gene amplicon sequencing using MiSeq. Amplicon based sequence variants (ASV) were analyzed by QIIME based bioinformatics to determine relative abundance of taxa, alpha- and beta-diversity.

Results: A significant difference in the alpha diversity metric Shannon Index was not observed between groups at study completion (Bioactive: 6.6 ± 0.6, CHX: 6.2 ± 0.7; p=0.217). The Observed Species Level was significantly lower in the CHX rinse group compared to the bioactive rinse group (Bioactive: 471.2 ± 95.6, CHX: 374.0 ± 71.8; p=0.003). In contrast, beta-diversity was significantly different between the two groups using Bray-Curtis (p=0.012) or unweighted unifrac (p=0.001). Kruskal-Wallis analysis found that compared to the CHX rinse group at study completion, the bioactive rinse group had significantly greater (p < 0.05) mean relative abundance of genera with established nitrate- or nitrite-reducing properties including Veillonella (Bioactive: 1.04%, CHX: 0.38%), Haemophilus (Bioactive: 0.11%, CHX: 0.05%), and Staphylococcus (Bioactive: 1.49%, CHX: 0.94%).

Conclusions: Results suggest a mouth rinse infused with inorganic nitrate and antioxidants favorably modulates oral microbiome composition in support of the enterosalivary pathway. Continued investigation of routine products and ingredients with the potential to influence the oral microbiome is warranted to promote optimal vascular health.

Funding Sources: AND Foundation Colgate Palmolive Fellowship in Nutrition, Oral Health/Dental Education