Chemical constituent and antimicrobial effect of essential oil from Myrtus communis leaves on microorganisms involved in persistent endodontic infection compared to two common endodontic irrigants: An in vitro study

INTRODUCTION: Persistent infections of human root canals play a fundamental role in the failure of endodontic treatment. The purpose of this study is to determine the chemical composition of Myrtus communis (M. communis) essential oil and to assess its antimicrobial activity against Enterococcus faecalis, Staphylococcus aureus and Candida albicans compared to that of sodium hypochlorite (NaOCl) and chlorhexidine (CHX). MATERIALS AND METHODS: Gas chromatography-mass spectrometry (GC-MS) was used to determine the chemical composition of essential oil from M. communis leaves. A micro-dilution susceptibility assay and disk diffusion methods were utilized to evaluate the antimicrobial activity [minimum inhibitory concentration (MIC) and minimum lethal dose concentration] of the tested solutions against selected microorganisms. RESULTS: GC-MS analyses revealed that M. communis contained 1, 8-Cineole (28.62%), α-Pinene (17.8%), Linalool (17.55%), and Geranylacetate (6.3%) as the major compounds and Geraniol (1.6%), α-Humulene (1.5%), eugenol (1.3%), isobutyl-isobutyrate (0.8%), and methyl chavicol (0.5%) as minor components. Chlorhexidine had the lowest MIC value among all medicaments tested. M. communis oil had less MIC values than NaOCl against both bacteria, but it had more MIC value against C. albicans. CONCLUSION: M. communis essential oil with the minimum inhibitory concentration in the range of 0.032-32 μg/mL was an effective antimicrobial agent against persistent endodontic microorganisms.