Chemical composition and antimicrobial activity of extracts from thyme and rosemary against Staphylococcus aureus and Candida albicans

Abstract

Different concentrations of ethanolic extracts of thyme (Zataria multiflora) and rosemary (Rosmarinus officinalis) were evaluated to determine their antimicrobial activity using the agar-well diffusion method. The values of inhibition zone diameter (IZD) for Candida albicans fungus and Staphylococcus aureus Gram-positive bacteria were determined. The bioactivities of two various extracts were studied, and the chemical composition of the extracts were identified using gas chromatography-mass spectrometry (GC-MS) technique. The results of the test showed that at concentrations of 10% and 40% thyme extract, the values of IZD were 12.5 mm and 23.3 mm, respectively, against the growth of S. aureus, which were higher than C. albicans (7.0 mm and 22.5 mm, respectively). The rosemary extract at concentrations of 20% and 60% showed lower antibacterial activity against S. aureus (4.7 mm and 8.7 mm IZD, respectively) and lower antifungal activity against C. albicans (12.2 mm and 1.7 mm IZD, respectively). At a concentration of 40% thyme extract, the highest antibacterial (23.3 mm IZD) and antifungal (22.5 mm IZD) activities were observed. The GC/MS analysis showed that carvacrol (52.3%), linalool L (16%), and thymol (9.6%) were the main components of thyme extract, while in the rosemary extract β-amyrone (18.0%), verbenone (8.0%), and 1,8-cineole (7.26%) were the major constituents.