Chemical composition and antimicrobial activity of essential oil from seeds of Anethum graveolens growing in Uzbekistan

Abstract

We have previously studied the chemical composition of essential oil (EO) from seeds of Anethum graveolens from Xinjiang Autonomous District in the PRC [1]. The component composition of essential oils is known to depend on the habitat. It seemed interesting to compare the composition and biological activity of EO from dill seeds growing in China and Uzbekistan. We used GC—MS to establish the structures of the isolated compounds. EO from seeds of A. graveolens (2007 harvest) that were collected in Tashkent Oblast was isolated by steam distillation in 4.2% yield. The chemical composition of the EO was studied using a Perkin—Elmer Turbo GC—MS. The component content of the oil was calculated using areas of GC peaks of total ion current without correlation coefficients. EO components were identified by comparing retention times and mass spectra of the component obtained in mass scanning mode and by using mass-spectral library data for standard oil components and pure compounds. A total of 22 chemical compounds was identified in EO of A. graveolens seeds growing in Uzbekistan. Table 1 lists the chemical composition of the EO. The principal EO components from dill seed growing in Uzbekistan were carvone (73.61%), limonene (14.69), cis-dihydrocarvone (5.87), diplaniol (1-allyl-2,5-dimethoxy-3,4-methylenedioxybenzene) (2.16), and 1,2-diethoxyethane (1.43%), which together made up 99.2% of the total EO component composition. The principal components of EO from dill seed growing in China were n-pentacosane (27.96%), dioctylester of 1,2-phenyldicarboxylic acid (25.10), octacosane (13.81), tricosane (9.14), and n-nonacosane (6.85%) [1]. A comparison of our data with that obtained earlier indicated that both the qualitative and quantitative composition of the principal EO components of A. graveolens growing in different geographic zones differed considerably. The high content in the studied EO of carvone, which is widely used as a growth inhibitor of bacteria [2-4] and certain fungi [5] and as a repellent [6] is noteworthy. Both S-(+)-carvone and R-(-)-carvone are used in the food industry to produce flavors [4] and in agriculture. For example, S-(+)-carvone is used in the Netherlands to prevent premature sprouting of potato tubers and tulip bulbs during storage [7, 8]. Carvone is an available and inexpensive reagent for organic synthesis in both enantiomeric forms. This makes it attractive for asymmetric synthesis of natural compounds [9]. Antimicrobial activity of EO fractions toward Candida albican and Staphylococcus aureus was estimated using the Barry method to determine the minimal inhibiting concentration (MIC) [10]. Growth of microorganisms decreased markedly upon addition of EO to nutrient medium. The experimental results are given below: