Identification of Volatile Oil Components of Nepeta binaludensis Jamzad by GC-MS and 13C-NMR Methods and Evaluation of its Antimicrobial Activity

Abstract

The essential oil of the aerial parts of Nepeta binaludensis Jamzad, an endemic species to Iran, was obtained by hydro-distillation and analyzed by GC, GC-MS and then 13C-NMR spectra of the main compounds. Sixty-five components, representing 97.42 % of the oil were identified. The major components of the oil were 1,8-cineol (68.31 %), α-terpineol (5.24 %), β-pinene (4.74 %), δ-terpineol (2.57 %), α-pinene (1.54 %). The minimum inhibitory concentrations (MICs) and minimum cidal concentrations (MCCs) of the essential oil and it's major component, 1,8-cineol, as authentic compound were determined using broth dilution method against four bacteria and one fungus. The essential oil was moderately active against Bacillus cereus (3.125 mg/ml), Escherichia coli (3.125 mg/ml), Staphylococcus aureus (6.25 mg/ml) and Candida albicans (12.5 mg/ml) with the same MIC and MCC values in each case. Another gram negative bacteria, Pseudomonas aeroginosa, appeard not to be susceptible to inhibitory effects of the essential oil. The obtained MIC and MCC values for 1,8-cineol were closely near to the essential oil values.