A Comparative Evaluation of the Antimicrobial Properties of 50% Grape Seed Extract, N-acetyl Cysteine and 5.25% Sodium Hypochlorite against Enterococcus faecalis (ATCC 19433) – An In vitro Study

Introduction: Endodontic infections are complex and polymicrobial, presenting significant challenges in dental treatment. Eliminating bacteria is the main objective of endodontic preparation, ensuring a tight seal to prevent reinfection. A commonly isolated bacterium, Enterococcus faecalis , is Gram positive and facultative anaerobic. It thrives in low-nutrient environments, forming resilient biofilms. Due to its tissue dissolving properties and broad-spectrum antimicrobial, sodium hypochlorite (NaOCl) is the most sought after irrigant, but its cytotoxicity is a concern. Alternatives such as grape seed extract (GSE) and N-acetyl cysteine (NAC) are being explored for their potential antimicrobial effects and biocompatibility. Materials and Methods: Forty single-rooted, non-carious premolars extracted for orthodontic reasons were selected. Teeth were cleaned, sectioned and prepared, ensuring apical patency. Specimens were autoclaved and contaminated with E. faecalis (ATCC 19433) for 30 days. Four groups ( n = 10) were formed: Group I – GSE 50%, Group II – NAC 200 mg/ml, Group III – NaOCl 5.25% and Group IV – sodium chloride (0.9%). Manufacturer’s instructions were followed precisely to prep the solutions, and root canals were treated using the Reciproc R25 instrument. Samples were collected before (F1) and after (F2) instrumentation and irrigation. Colony-forming units (CFUs) were quantified and analysis was done using two-way analysis of variance and Tukey’s honestly significant difference post hoc tests, with significance set at P < 0.05. Results: NaOCl significantly reduced CFU counts, demonstrating superior antimicrobial efficacy compared to NAC and GSE ( P < 0.01). In comparison to negative control and GSE ( P < 0.01), NAC showed significant antimicrobial activity, but not significantly different from GSE ( P > 0.05). GSE displayed potential antimicrobial properties but was less effective than NaOCl and NAC. Conclusion: NaOCl remains the most effective irrigant; however, NAC and GSE also demonstrated significant antimicrobial properties and could serve as adjuncts in endodontic therapy. Further research is needed to optimise their formulations and validate clinical applications.