Chemical constituents of (Roth) G. Don essential oil and their antimicrobial activity against Gram-positive and Gram-negative bacteria, filamentous fungi and .

The aerial parts of (Roth) G. Don were subjected to hydrodistillation to obtain essential oils which had been analyzed by gas chromatography and gas chromatography coupled with mass spectrometry and tested for antimicrobial activity against 12 bacteria, two yeasts and four fungi by agar diffusion method. The essential oil yielded 0.44% (v/w) and 67 compounds accounting for 99.24% of the oil were identified with a high content of oxygenated sesquiterpenes (61.42%). The most oxygenated sesquiterpene compounds were α-Cedrene (13.61%), α-Curcumene (11.41%), Geranyl acetate (10.05%), Limonene (6.07%), Nerol (5.04%), Neryl acetate (4.91%) and α-Pinene (3.78%). The antimicrobial activity of the essential oil was assayed by using the disk diffusion method on ATCC 25922, ATCC 6538, ATCC 4698, ATCC 4352, ATCC 2035, ATCC 10876, ATCC 12228, ATCC 9372, ATCC 27853, ATCC 49452, ATCC 35659, ATCC 15313 and yeasts ATCC 10231, ATCC 9763 and fungi, var. , , , . inhibited the growth of all the tested microorganisms except three bacteria, ATCC 25922, ATCC 4352 and ATCC 15313. The most sensitive bacterium was with minimum inhibitory and bactericidal concentrations of 0.79 μg ml. A minimum fungistatic and fungicide concentration of 6.325 μg ml and 12.65 μg ml respectively was obtained with ATCC 10231 and ATCC 9763. However the four fungi were more resistant with fungistatic minimum concentration ranging from 6.325 μg ml to 50.6 μg ml and a fungicide minimum concentration of 50.6 μg ml. This antimicrobial activity could be attributed to the essential oil chemical composition. Thus this study represents a first step in the study of the chemical composition of (Roth) G. Don collected from north Algeria and its antimicrobial properties.