Chemical composition and antimicrobial activity of Teucrium arduini essential oil and cirsimarin from Montenegro

Essential oil from Teucrium arduini was analyzed by gas chromatography flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Fifty-two components were identified (99.52% of total) and quantified by calculating the response factors of FID. The oil was dominated by sesquiterpenes, which accounted for 55.57% of the oil. This study indicates the presence of a high percentage of sesquiterpene hydrocarbons (48.76%), of which the main constituents were germacrene D (16.98%) and beta-caryophyllene (14.98%). The minimum inhibitory concentration (MIC) values of the oil obtained by using broth microdilution method were within the range of 50 to 6.25 mu l/ml. Maximum activity was observed against gram negative bacteria Klebsiella pneumonia (6.25 mu l/ml). In addition, at MIC value of 25 mu l/ml, essential oil showed a good activity against gram positive bacteria Staphylococcus aureus (ATCC 25923) and S. aureus (FSB 30), as well as Gram negative bacteria E. cloaceae (FSB 22) and Proteus mirabilis (FSB 34). On the other hand, at the concentration of 31.25 mu g/ml isolated cirsimarin showed a strong activity against K. pneumonia.