Composition and antimicrobial activity of essential oils of some medicinal and spice plants

Abstract

An examination was made on the chemical composition and antimicrobial activity of four medicinal plants Carum carvi, Coriandrum sativum, Hyssopus officinalis, and Eucalyptus globulus, the first three of which are also used as culinary spice herbs. Carum carvi L. and Coriandrum sativum L. belong to the Apiacea family. In traditional medicine, Carum carvi is used in the form of a tea as a digestive and diuretic [1]. Coriandrum sativum has been used since ancient times; it was found in pharaonic tombs where it was used for embalming, and there is mention of it in the Bible. It is used as a medicine against flatulence and as a diuretic [1], and it also has an anticonvulsive effect [2]. The essential oils of these two plants are used as spices in preparing food. Hyssopus officinalis L. and Eucalyptus globulus Lab. belong to the Lamiaceae and Myrtaceae families, respectively, and they are used in folk medicine to treat respiratory diseases [1]. The aim of this paper was to determine the chemical composition of the essential oils of the said plants and examine their activity against the growth of bacteria (Staphylococcus aureus ATCC 25923, Streptococcus haemolyticus group A, Escherichia coli ATCC 25922, Enterecoccus faecalis ATCC 29212, and Pseudomonas aeruginosa ATCC 27853), and fungi (Candida albicans ATCC 10231). Eucalyptus globulus was collected at the Montenegrin Coast and all the rest of the plants were grown in the fields of Vojvodina (Northern Serbia). The essential oils were obtained from the fruits of Carum carvi and Coriandrum sativum and the leaves of Hyssopus officinalis and Eucalyptus globulus by the steam distillation method following Procedure III of the Yugoslav Pharmacopoeia [3]. The GC and GC/MS analyses were used for determination of the essential oil composition. Percentages of the main components of the essential oils investigated are given in Table 1. The essential oils of the plants examined are of different chemical compositions, and monoterpenes are distributed the most. By comparison of the composition of the essential oils of the plants mentioned with the literature data [4] and [5], it was concluded that it was dependent on the geographic region and plant growing conditions. The antimicrobial activity of the essential oils of the plants investigated was determined by the disc-diffusion method [6] and [7]. Tables 2 gives MIC (minimum inhibitory concentration) values and inhibition zone diameters for three different essential oil concentrations. The inhibition zone diameters were compared with the reference antibiotics, as shown in the tables. As Enterecoccus faecalis ATCC 29212and Pseudomonas aeruginosa ATCC 27853 were not inhibited by the essential oils of the plants mentioned, their results are not given in the Tables. The broadest inhibitory activity spectrum was exhibited by the essential oils of Carum carvi and Hyssopus officinalis, and the narrowest one by Eucalyptus globulus. The antimicrobial activity of certain oils (Carum carvi, Hyssopus officinalis, and Eucalyptus globulus) against Staphylococcus aureus ATCC 25923 was higher than or equal to the reference value. A pronounced activity against Candida albicans ATCC 10231 was also expressed by all the essential oils with the exception of the essential oil of Hyssopus officinalis.