Cranberry Polyphenol Extract (CPE) Oral Rinse Improves Salivary Microbiome in 6-n-Propylthiouracil (PROP) Non-Tasters and Palatability of Aronia Juice

Sensitivity to the bitterness of 6-n-propylthiouracil (PROP) is controlled by variations in the TAS2R38 gene. This phenotype is often used as a marker for individual differences in taste perception. Previous findings show that PROP taster status is associated with differences in the salivary microbiome. It is well known that diet and environmental factors influence the risk of oral disease, but there is far less evidence showing how genetic differences play a role. Forty-seven young, healthy, PROP taster-classified adults rinsed with a cranberry polyphenol extract (CPE) oral rinse (0.75 g/L CPE powder in spring water) twice daily for 11 days. Saliva was collected pre- and post-intervention for microbiome analysis using shotgun metagenomic sequencing. At the same time points, participants evaluated two astringent juices (cranberry and aronia berry) for key attributes. At baseline, PROP taster groups differed in their salivary microbiome compositions, but post-intervention, the groups had more similar bacterial compositions. Post-intervention, non-tasters showed decreases in the relative abundance of 15 bacterial species, including a significant reduction (p = 0.037) in Eikenella corrodens, which is one bacterium, among several others, involved in oral biofilm formation. Additionally, after the intervention, sourness was reduced, and overall liking increased significantly for aronia juice. Oral dysbiosis, a risk factor for oral disease, may be controlled by bactericidal mouthwashes. Our results suggest that CPE, a natural alternative to traditional bactericidal rinses, may selectively target pathobionts while preserving salivary microbiota diversity. CPE might also provide greater benefits to non-tasters, who are at greater risk for oral disease.