Comparison of Biological Activity and Chemical Constituents of the Essential Oils from Leaves of Thymus caucasicus, T kotschyanus and T vulgaris

Abstract

A comparison of the chemical composition, antioxidant and antibacterial activity of the essential oils obtained from the leaves of Thymus caucasicus Willd., T. kotschyanus Boiss. & Hohen., and T. vulgaris (L.) were carried out. The oils were obtained by hydrodistillation and were analyzed by GC and GC-MS. Twenty constituents representing 94.8 % of the essential oil of T. caucasicus, twenty - nine components 96.6 % of the T. kotschyanus oil and twenty two compounds 98.2 % of the T. vulgaris leaf oils have been identified. The oil of T caucasicus leaf was characterized by higher amounts of 1,8-cineol (21.5 %), thymol (12.6 %), β-fenchyl alcohol (8.7 %), nerolidol (7.8 %), terpinolene (7.2 %), a-pinene (7.0 %) and myrcene (6.8 %). In the oil of T kotschyanus leave, carvacrol (24.4 %), β-caryophyllene (14.5 %), y-terpinene (12.4 %), a-phellandrene (10.8 %), p-cymene (9.8 %) and thymol (6.8 %) were the predominant compounds, while the main components of the oil of T vulgaris leaves were thymol (43.8 %), p-cymene (15.2 %) germacrene-D (11.7 %), terpinolene (3.4 %), carvacrol (3.2 %), β-caryophyllene (2.8 %) and a-thujene (2.2 %). In the plant oils, the hydrocarbon monoterpenes compounds predominated over sesquiterpenes. Antioxidant activity was tested according to the DPPH radical scavenging method with measurement of sample concentration providing 50 % inhibition (IC50). Antibacterial activity was determined by measurement of the minimum inhibitory concentration (MIC) using the broth dilution method. The essential oils of T caucasicus, T kotschyanus and T vulgaris Showed free radical scavenging and antibacterial activity.