Antimicrobial Efficacy of a Novel Irrigant, Nigella–Eugenia Oil Composite against Enterococcus faecalis and Candida albicans

Abstract

Aim: The aim of this study was to develop a novel herbal irrigant Nigella–Eugenia oil composite (NEOc) and check its antimicrobial efficacy against Enterobacter faecalis and Candida albicans and compare it with standard chemical irrigants like sodium hypochlorite and chlorhexidine. Materials and methods: Soxhlet method was chosen to extract the content from Nigella sativa and Eugenia caryophyllus herbs. Minimum inhibitory concentration (MIC)/minimal bactericidal concentration (MBC)/minimal fungicidal concentration (MFC) of N. sativa and E. caryophyllus (ethanol extracts) against E. faecalis and C. albicans was determined by well diffusion method. A novel composite NEOc was developed and its antimicrobial activity was evaluated in terms of zone of inhibition around the wells in the inoculated Mueller–Hinton agar (MHA) plates and compared with sodium hypochlorite and chlorhexidine. Results: About 300 µg/mL of test concentrate was selected as the MIC and MBC/MFC value for the test organism for both N. sativa and E. caryophyllus extracts. Antimicrobial activity of the extracts showed good inhibitory zones. The antimicrobial activity of NEOc against E. faecalis and C. albicans was found maximum of 21 and 22 mm, respectively. The obtained results conformed the synergism behavior of two herbal extracts natively present in the developed composite. The cell viability percentage of the developed NEOc was more than 99% for all the test concentrations indicating its biocompatibility. Conclusion: The developed novel NEOc’s antimicrobial activity against E. faecalis and C. albicans was found to be slightly higher than 2.5% sodium hypochlorite and 2% chlorhexidine. Clinical significance: The developed novel NEOc have the potential to be used as an alternative to chemical irrigants like sodium hypochlorite and chlorhexidine and decrease the incidence of endodontic treatment failures resulting from resistant bacteria like E. faecalis and C. albicans.