The Effect of Medium-Chain Triglycerides Oil on Candida albicans and Streptococcus mutans in Planktonic and Mucosal Models

Abstract

Despite MCT oil's potential antimicrobial benefits for gastrointestinal health, its effects on disrupting cariogenic pathogens on oral mucosal surfaces remain underexplored. This study evaluated the impact of MCT oil on the adhesion and invasion of Candida albicans and Streptoccocus mutans using planktonic and mucosal models. First, a planktonic model was used to assess the impact of various concentrations of MCT on the growth of S. mutans and C. albicans. Subsequently, a mucosal model was established by seeding TR-146 human buccal mucosal epithelial cells on a 3 µm porous transwell membrane, forming an epithelial barrier. MCT oil was then applied to the epithelial barriers in different durations (10, 30, and 60 min). Subsequently, C. albicans and S. mutans were introduced in the transwell and their adherence to the epithelial cells and their transmigration through the barriers was assessed using colony-forming unit counts and the barrier integrity was assessed by trans epithelial electrical resistance (TEER). Furthermore, cytotoxicity of MCT oil on mucosal cells was assessed by AlamarBlue assay. We found that higher MCT concentrations (90% and 100%) significantly inhibited C. albicans and S. mutans growth in planktonic conditions. Additionally, MCT oil reduced S. mutans adhesion to epithelial cells, highlighting its potential to interfere with bacterial attachment and colonization to oral mucosa. However, the oil had limited effects on C. albicans adhesion and transmigration. MCT demonstrated no cytotoxic effects on the viability of epithelial cells. The study findings highlight the potential benefits of MCT oil, particularly in oral bacterial inhibition, for oral health applications.

Keywords: C. albicans; MCT oil; S. mutans; adherence; epithelial barrier; transmigration.

Figure 1

Effect of MCT on C. albicans and S. mutans in single- and dual-species planktonic models. (a) The growth of C. albicans cultured with varying concentrations of MCT. (b) The growth of C. albicans cultured with varying concentrations of MCT in the presence of S. mutans. (c) The growth of S. mutans cultured with varying concentrations of MCT in the presence of C. albicans. One-way ANOVA was used to compare the CFU counts (converted to natural log value). * A two-sided p-value which showed significant differences between MCT-treated (90% and 100% MCT) and untreated control groups was reported.

Figure 2

Viability of oral epithelial cells after varying exposure durations to MCT, as measured by alamarBlue assay. Oral epithelial cell viability was assessed after exposure to MCT for different durations. One-way ANOVA was used to compare the absorbance values. No significant difference between MCT-treated and untreated control groups was found when a two-sided p-value was reported.

Figure 3

Effect of MCT on the adherence of C. albicans and S. mutans to oral epithelial cells. (a) Quantification of C. albicans adherence to epithelial cells, with and without MCT pre-treatment. (b) Quantification of S. mutans adherence to epithelial cells, with and without MCT pre-treatment. One-way ANOVA was used to compare the CFU counts (converted to natural log value). * A two-sided p-value which showed significant differences between MCT-treated and untreated control groups was reported.

Figure 4

Effect of MCT on the transmigration of C. albicans and S. mutans through oral epithelial barrier. (a) Quantification of transmigrant C. albicans into the lower chamber, with and without MCT pre-treatment. (b) Quantification of transmigrant S. mutans into the lower chamber, with and without MCT pre-treatment. One-way ANOVA was used to compare the CFU counts (converted to natural log value). No significant difference between MCT-treated and untreated control groups was found when a two-sided p-value was reported.

Figure 5

TEER (transepithelial electrical resistance) measurements of the oral epithelial barrier during C. albicans and S. mutans infection. (a) TEER measurements of the epithelial barrier during C. albicans infection, with and without MCT pre-treatment. (b) TEER measurements of the epithelial barrier during S. mutans infection, with and without MCT pre-treatment. One-way ANOVA was used to compare the TEER measurements. * A two-sided p-value which showed significant differences between MCT-treated and untreated control groups was reported.