Chemical composition and antimicrobial activity of essential oil from Minthostachys mollis against oral pathogens

Abstract

Introduction: Minthostachys mollis is medicinal plant frequently used because of its anti-inflammatory and antibacterial properties. Objective: Identify the chemical composition of the essential oil from Minthostachys mollis and evaluate its antimicrobial properties against oral pathogens. Methods: The essential oil was extracted from the fresh leaves and branches of the plant by steam distillation method, and Gas Chromatography-Mass Spectrometry were performed to identify the principal constituents of the essential oils. Repetitions for the antimicrobial assay were calculated with the Epi info TM program. The antimicrobial activity was tested against Enterococcus faecalis ATCC 29212, Porphyromonas gingivalis ATCC 33277 and Candida albicans ATCC 10231 by disc diffusion assay and microdilution method, the minimum inhibitory concentration, minimum bacterial concentration and minimum fungal concentration were recorded. Results: The main compounds found were menthone (32.9%) and eucalyptol (28.1%). The essential oil of M. mollis demonstrated inhibition zones against E. Faecalis, P. gingivalis and C. albicans of 15.13 ± 0.39, 17.96 ± 0.21, and 20.82 ± 0.63 mm, respectively. There were significant differences on the inhibition zones between the three strains tested, being C. albicans the most sensible microorganism (p < 0.05). The minimum inhibitory concentration ranged from 1.05 to 2.11 µg/mL, the minimum bacterial concentration ranged from 2.11 to 4.23 µg/mL, and the minimum fungal concentration was 1.05 µg/mL. Conclusions: The essential oil of Minthostachys mollis showed as principal compounds menthone and eucalyptol and it has an important antimicrobial activity against E. faecalis, P. gingivalis and C. albicans.

Keywords

• minthostachys mollis
• plant oils
• chemical composition
• antibacterial agents.