Comparative Evaluation of the Antimicrobial Efficacy of Selected Herbal Preparations and 5.2% Sodium Hypochlorite against Enterococcus faecalis: An in Vitro Original Research Study

Abstract

Background

Effective microbial control is an essential component of successful endodontic treatment. Although cleaning and shaping and the use of antimicrobial agents substantially reduce the bacterial load within the root canal system, residual microorganisms may persist and contribute to reinfection. The potential adverse effects and safety concerns associated with some synthetic antimicrobial agents have stimulated interest in plant-derived alternatives.

Aim

The present in-vitro study aimed to qualitatively evaluate the antimicrobial efficacy of four herbal preparations—Mimusopselengi (Bakula), Azadirachta indica (Nimba), Acacia arabica (Babul), and Syzygium aromaticum (Lavanga)—and compare their activity with 5.2% sodium hypochlorite against Enterococcus faecalis.

Materials and Methods

Four raw herbal drugs comprising the bark of Mimusopselengi, bark of Azadirachta indica, bark of Acacia arabica, and flowers of Syzygium aromaticum were selected. Concentrated herbal preparations were prepared using the decoction method. A standard strain of E. faecalis was subcultured and used to contaminate cleaned extracted teeth. The teeth were autoclaved at 121°C and 15 psi for 15 minutes and subsequently maintained in E. faecalis Brain Heart Infusion broth for 21 days. The broth was changed every 7 days while maintaining turbidity equivalent to a 0.5 McFarland standard, approximately 1.5 × 10^8 CFU/mL. Each test solution was applied to one tooth for 15 minutes. Following exposure, the tooth surface was sampled using a sterile swab and inoculated onto one-quarter of a Petri dish. Bacterial growth was assessed after 24 hours of incubation.

Results

The herbal preparations demonstrated variable antimicrobial activity against E. faecalis. No bacterial growth was observed following exposure to Syzygium aromaticum. The 5.2% sodium hypochlorite group demonstrated fair growth. Acacia arabica and Azadirachta indica demonstrated moderate growth, whereas Mimusopselengi demonstrated heavy growth.

Conclusion

Within the limitations of this qualitative preliminary investigation, Syzygium aromaticum demonstrated the greatest apparent antimicrobial activity among the tested herbal preparations and showed no detectable growth following the experimental exposure period. The findings suggest that S. aromaticum warrants further investigation as a potential herbal endodontic irrigant. However, larger controlled studies using standardized preparations, adequate replication, quantitative microbiological assessment, and appropriate statistical analysis are required before clinical application can be recommended.