Diversity of antibacterial and antifungal activities of Thymus kotschyanus essential oil collected from fourteen regions of Iran

Abstract

Background and Aim: Thymus kotschyanus is one of the most famous medicinal plants in Iran from the mint family and it has many applications in traditional medicine, such as relieving the symptoms of colds and coughs and relieving some gastrointestinal diseases. It also has antibacterial and antifungal effects. This study was performed to investigate the diversity of antibiotic effects of this plant. Materials and Methods: Essential oils of fourteen different ecotypes of Thymus kotschyanus were extracted by using the Clevenger apparatus. After oil analyses with GC-MS device, the minimum inhibitory concentration of growth and also the minimum lethal concentration of 7 types of bacteria and 2 types of fungi were measured by microdilution method in the range of 0.01 to 5.12 mg/ml. Results: Oxygenated monoterpenes were the major fraction (64.60–90.60%) of the oils, and thymol and carvacrol were considered as the most abundant constituents (27.23–75.55%). The amount and concentration of these two phenolic substances in thyme essential oil were directly related to antibacterial and antifungal effects. The antibacterial and antifungal activity of the essential oils ranged from 0.24 to 5.12 and 0.08 to 0.96 mg/ml, respectively. The most active antimicrobial activity is related to the essential oil of Salmas and Nodoshan ecotypes and the least activity was seen in Rudbar ecotype. Conclusion: Geographical characteristics of the place where plants grow had a significant role in the type and amount of compounds in the essential oil of the plant. In this regard, different biological effects and antibacterial and antifungal properties can occur from each ecotype.