Essential Oil and Bioactivity of the Ziziphora canescens Benth. Growing Wild in Lebanon

Abstract

Introduction: Ziziphora canescens Benth. (Lamiaceae) is a medicinal plant widespread species in Mediterranean countries. This study was designed to evaluate the chemical composition and in vitro antimicrobial activities of this species growing wild in Lebanon.Material and Methods: The essential oil of the dry aerial flowering parts of Z. canescens from the Lebanese side of Mount Hermon (1843 m altitude above sea level) was obtained by hydrodistillation. The GC-MS analysis of the obtained essential oil was performed. The antimicrobial activity of the oil was tested against six certified bacteria and two certified fungi using disc-diffusion method and determination of the minimal inhibitory concentration (MIC) by agar dilution method. Results and Discussion: The yield of essential oil was 0.6ml/100g dry weight. GC -MS analysis revealed twenty eight components representing 93.0% of the total essential oil. Oxygenated monoterpenes (80.6%) were the predominant fraction of the essential oil with pulegone (39.2%), eucarvone (12.6%), D-menthone (10.3%), 3-cyclohexen-1-one, 2-isopropyl5-methyl- (9.1%). The oil exhibited a broad-spectrum of antimicrobial activity against the tested pathogenic microorganisms. The yeast Candida albicans and Salmonella enteritidis were the most susceptible with growth inhibition zones of 40.5 ± 0.7 mm and 29.0 ± 0.7 mm, respectively, and MIC values of 5µg/ml. These values were similar to those of pulegone and each the antibiotics Nystatine and Amikacine, respectively whilst, the fungus Trichophyton mentagrophytes was the most resistant.Conclusion: The results of this study support the notion that the essential oil of Z. canescens Benth. may be important as a pharmaceutical and food preservative.

Keywords: Antimicrobial activities; Chemical composition of essential oil; Eurcarvone; Pulegone; Ziziphora canescens Benth