Abstract
BACKGROUND: Streptococcus mutans is a virulent microorganism associated with dental caries. This in vitro study aimed to investigate the antimicrobial effects of Cholecalciferol (D3) and Doxercalciferol (D2), against S. mutans and on glycosyltransferase gene expression. METHODS: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of D3 and D2 for S. mutans were determined according to the Clinical Laboratory Standards Institute guidelines. The effect of the compounds on environmental pH in 1% w/v and 5% w/v sucrose broth cultures after 24 hours were assessed colorimetrically. Additionally, their impact on glycosyltransferases gene expression (GtfB, GtfC, GtfD) in 5% w/v sucrose culture was evaluated using quantitative real-time PCR. RESULTS: The MBCs of D3 and D2 were 83 µg/ml and 166 µg/ml respectively. Both compounds were effective in preventing the local pH drop <5.5 at ≥166 µg/ml in sucrose supplemented cultures. However, the compounds did not inhibit pH drop at MIC values. Notably, D2 upregulated GtfD expression significantly (p < 0.05) and downregulated GtfB and GtfC. CONCLUSION: Vitamin D2 and D3 inhibited S. mutans mediated pH drop in sucrose supplemented cultures and altered glycosyltransferase expression, suggesting potential therapeutic roles in dental caries prevention. Further research is needed to assess their full impact on S. mutans survival under environmental stresses.