Inhibition Of Streptococcus Mutans Adherence And Biofilm Formation Activities From Melastoma Malabathricum Subfraction

Objectives: The objectives of the study were to determine antibacterial, anti-adherence, and antibiofilm ctivities of Melastoma malabathricum stem bark acetone extract (MMSBAE) subfraction against Streptococcus mutans.
Methods: Fraction 9 (F9) from MMSBAE was subfractionated by thin-layer chromatography (TLC) and analyzed for antibacterial activity against S. mutans by TLC-bioautography. Subfraction 12 (SF12) was isolated from F9 followed by determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. Results: MIC and MBC values were 10 mg/mL and 160 mg/mL, indicating bacteriostatic property of SF12. Time-kill assay analysis confirmed bacteriostatic property of SF12 against S. mutans. Crystal violet staining and glass surface assays were used to determine anti-adherence and antibiofilm
activities. Concentrations produced 50% reduction in anti-adherence and antibiofilm activities were 40 mg/mL and 20 mg/mL, respectively. Scanning electron microscopy was performed to visualize the effect of SF12 on S. mutans biofilm structure. SF12 was found to lyse biofilm formation on treated bacteria indicating powerful anticariogenic potential against S. mutans. Analysis by quantitative real-time polymerase chain reaction revealed SF12 at MIC value downregulated biofilm formation genes such as gbpA, brpA, gtfC, and comDE.
Conclusion: SF12 showed bacteriostatic activities against S. mutans by inhibiting adherence and biofilm activities.