Tongue coating metabolic profiles of intra‐oral halitosis patients

Abstract Objective This study focused on the metabolic characteristics of tongue coating in patients with intra‐oral halitosis (IOH) to investigate potential diagnostic biomarkers for IOH. Methods Oral healthy participants were enrolled in this study. Halitosis was evaluated with an organoleptic assessment, a Halimeter®, and an OralChroma™. Tongue coating samples were collected from 18 halitosis patients and 18 healthy controls. Liquid chromatography–mass spectrometry was conducted to reveal the IOH‐related metabolic variations in tongue coating. Results A total of 2214 metabolites were obtained. Most metabolites were shared between the two groups. A total of 274 upregulated metabolites, such as paramethasone acetate and indole‐3‐acetic acid, and 43 downregulated metabolites, including deoxyadenosine and valyl‐arginine, were detected in the halitosis group. Functional analysis indicated that several metabolic pathways, including arginine biosynthesis, arginine and proline metabolism, histidine metabolism, and lysine degradation were significantly enriched in the IOH group. The least absolute shrinkage and selection operator logistic regression analysis revealed that paramethasone acetate, {1‐[2‐(4‐carbamimidoyl‐benzoylamino)‐propionyl]‐piperidin‐4‐yloxy}‐acetic acid, indole‐3‐acetic acid, and valyl‐arginine were remarkably associated with IOH. Conclusions This study revealed the metabolites present in tongue coating and identified effective biomarkers, providing essential insights into the prediction, pathogenesis, and diagnosis of IOH.