Iranian Journal of Medical Microbiology

Background & Objective: Prolonged use of chemical agents to control cariogenic bacteria is frequently associated with adverse side effects. Consequently, increasing attention has been directed toward replacing conventional chemical antimicrobials with herbal alternatives. This study aimed to evaluate the in vitro antibacterial and anti-biofilm activities of curcumin nanoparticles against standard strains of Lacticaseibacillus casei and Lactobacillus acidophilus.
Materials and Methods: In this descriptive cross-sectional study, the minimum inhibitory concentration of nanocurcumin was determined and compared with that of chlorhexidine using the broth microdilution method. Chlorhexidine mouthwash served as the positive control, whereas physiological saline was used as the negative control. MICs were determined in 96-well microplates according to the Clinical and Laboratory Standards Institute guidelines. Anti-biofilm activity was assessed by a microtiter plate assay employing crystal violet staining. Data were analyzed using SPSS version 22, with statistical significance defined as p < 0.05.
Results & Conclusion: Chlorhexidine inhibited biofilm formation at concentrations of 6.25 µg/mL for L. acidophilus and 12.5 µg/mL for L. casei. Notably, nanocurcumin at a sub-MIC concentration of 3.125 µg/mL significantly reduced biofilm formation in both species (p < 0.05). Overall, curcumin nanoparticles exhibited distinct antibacterial and anti-biofilm effects against L. casei and L. acidophilus. Given their natural origin, favorable safety profile, and potential to overcome the limitations of synthetic antimicrobials, nanocurcumin formulations may represent a promising and biocompatible alternative for the prevention of dental caries.