Comparative Antibiofilm Activity of Indigenous Medicinal Plants and Chlorhexidine against Oral Pathogens: An In Vitro Experimental Study

Abstract

Background: Oral biofilms contribute substantially to dental caries, periodontal disease, and other oral infections, creating interest in plant-derived antibiofilm agents.
Aim: To compare the antibiofilm activity of Azadirachta indica, Ocimum sanctum, Syzygium aromaticum, and Curcuma longa with 0.12% chlorhexidine against selected oral pathogens.
Methods: This in-vitro experimental study evaluated 200 observations involving Streptococcus mutans, Streptococcus sanguinis, Enterococcus faecalis, and Candida albicans. Biofilm inhibition was assessed using optical density at 595 nm, while antimicrobial activity was additionally evaluated using changes in log10 CFU/mL. Six treatment groups were evaluated: 0.12% chlorhexidine, A. indica, O. sanctum, S. aromaticum, C. longa, and a negative control.
Results: Mean biofilm inhibition was 79.58% with chlorhexidine, 72.99% with S. aromaticum, 68.39% with A. indica, 63.67% with O. sanctum, 53.84% with C. longa, and 5.59% with the negative control. Treatment significantly affected biofilm inhibition (two-way ANOVA, p<0.001) and log10 CFU reduction (p<0.001), while pathogen type also showed significant effects. The treatment-by-pathogen interaction was not statistically significant for either outcome.
Conclusion: All four indigenous medicinal plants demonstrated measurable antibiofilm activity compared with the negative control, although their activity differed from 0.12% chlorhexidine. S. aromaticum demonstrated the highest antibiofilm activity among the tested plants, supporting further investigation of standardized clove preparations as potential oral antibiofilm agents.