Jelena Lazarević

Chemical composition and antioxidant and antimicrobial activities of essential oil of Allium sphaerocephalon L. subsp. sphaerocephalon (Liliaceae) inflorescences

BACKGROUND Allium sphaerocephalon is a wild-growing plant commonly used as an onion substitute. In this study the essential oil obtained from A. sphaerocephalon subsp. sphaerocephalon inflorescences was analysed by gas chromatography and gas chromatography/mass spectrometry and also evaluated for in vitro antioxidant and antimicrobial activities. The obtained results are reported for the first time and discussed with respect to the sulfur compounds detected in the essential oil. RESULTS Ninty-one compounds were identified, representing 91.6% (w/w) of the total oil. Major constituents of the analysed sample were shyobunol (15.3%), β-caryophyllene (8.1%), α-cadinol (7.8%), 3,5-diethyl-1,2,4-trithiolane (isomer II, 5.9%) and δ-cadinene (5.2%). The diluted oil had an antioxidant capacity of 160 000 ± 111 micromol α-tocopherol acetate equivalents g(-1). Its antimicrobial activity was evaluated against five bacterial and two fungal strains using the broth microdilution assay. Among the micro-organisms tested, the most susceptible strains were Pseudomonas aeruginosa (minimal inhibitory/bactericidal concentration = 0.08/2.5 mg mL(-1)) and Aspergillus niger (minimal inhibitory/fungicidal concentration = 0.31/0.63 mg mL(-1)). CONCLUSION The results showed that the examined species had strong antioxidant and antimicrobial properties and are in accordance with the popular use of plants belonging to the genus Allium in traditional medicine, emphasising the necessity of further detailed study of the active principles in Allium species.

Antimicrobial Activity of Nepeta rtanjensis Essential Oil

Abstract The antimicrobial activity and the composition of the essential oil of aerial parts of Nepeta rtanjensis Diklić et Milojević wild growing and cultivated in Serbia were evaluated. The main compound in both samples was characterized as 4aα,7α,7aβ-nepetalactone with 83.6% (wild) and 77.9% (cultivated). α-Copaene, germacrene D and δ-cadinene were present less than 5% in the oils. The antimicrobial activity of the oils was investigated by disk diffusion method. The oil-ethanol solution in three dilutions, tested against fve bacteria and a fungus, was effective towards all bacteria but not against Aspergillus niger. The oils showed bacteriostatic activity even in 1:60 dilution.

Composition of Achillea distans Willd. subsp. distans root essential oil

Gas chromatography and gas chromatography/mass specteometry analyses of root volatiles of Achillea distans Willd. subsp. distans, collected from wild populations in Serbia, enabled the identification of 185 constituents, accounting for 93.6% of the total oil. Main constituents of the oil were τ-cadinol (17.6%), alismol (14.1%), α-cadinol (9.1%) and caryophyllene oxide (5.0%). The root oil was additionally characterised by the presence of five different amides containing the olefinic C10 acid moieties. This is the first report on A. distans subsp. distans root volatiles and on the occurrence of piperidides and piperideides as essential oil constituents.

Recent Advances in Analysis of Essential Oils

This review provides an overview of the emerging trends in analysis of essential oils and indicates future trends. Since early human history the essential oils have been used in folk medicine, food and cosmetic industries in various parts of the world. GC-FID is the traditional method for essential oils quantification while GC-MS is the most common analytical method for qualitative analysis. Chiral GC allowed the identification of a great number of chiral essential oil constituents. An alternative to GC analysis is HPLC chromatography. The use of hyphenated techniques, such as LC-MS-MS provides important information about the structure of essential oils constituents. However, only a comparatively small number of reports on essential oil analyses by HPLC can be found in the literature. Multidimensional chromatography is an approach capable of providing greater resolution.13C-NMR spectroscopy is a complementary tool for analysis of essential oils. Advantage of this method compared to mass spectrometry is identification of stereoisomers and thermally unstable compounds while its disadvantage is inability to identify the minor oils constituents. 1H-NMR as an online tool for GC analysis showed promising results but requires further research to be applied on the analysis of essential oils. The range of information obtained from essential oils analysis enables the application of chemometrics (review).

Antimicrobial activity and cytotoxicity of some 2-amino-5-alkylidene-thiazol-4-ones.

We report a small, focused library of 30 diverse 2-amino-5-alkylidene-thiazol-4-ones that was assayed in a whole-cell antibacterial screen against a panel of several bacterial strains and a yeast. Most of the compounds exhibited modest to significant antibacterial activity against Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus, and no activity against Salmonella typhimurium and Escherichia coli. The antibacterial activity depends markedly upon substituents on the thiazol-4-one core, and the most potent compound assayed (

Chemical Analysis of Volatile Constituents of Berula erecta (Hudson) Coville subsp. erecta (Apiaceae) From Serbia

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Antimicrobial Activity of the Essential Oils of Selected Stachys Species

(Z)-4-((2-(4-methylpiperidin-1-yl)-4-oxothiazol-5(4H)-ylidene)methyl)benzonitrile) reached a minimal inhibitory concentration (MIC) value of