Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Chemical composition and antibacterial activity of the essential oils from Launaea resedifolia L | Zellagui et al. Organic and Medicinal Chemistry Letters 2012 2 2 http content 2 1 2 o Organic and Medicinal Chemistry Letters a SpringerOpen Journal ORIGINAL Open Access Chemical composition and antibacterial activity of the essential oils from Launaea resedifolia L Amar Zellagui1 Noureddine Gherraf1 Segni Ladjel2 and Samir Hameurlaine2 Abstract Background Several species of the genus Launaea are used in folk medicine such as in bitter stomachic skin diseases and reported to have antitumor insecticide and cytotoxic activities. The antimicrobial activities of coumarin constituents and the neuropharmacological properties have been investigated as well. In this study the chemical composition of essential oils from Launaea resedifolia L. has been identified using the ordinary GC-MS technique to reveal the presence of 19 compounds dominated by dioctyl phthalate. Moreover the antibacterial activity of the crude oil has been carried out using disk diffusion method against seven bacteria strains. Results Nineteen compounds of essential oil of L. resedifolia L. were identified representing of the total oil. The compounds were identified by spectral comparison to be mainly esters alcohols ketones and terpenes. The principal constituents are dioctyl phthalate Decanoic acid decyl ester 11-Octadecenal and Eucalyptol while others were present in relatively small amounts. As far as antibacterial essays are concerned it was found that the oils are active against most of the tested bacterial strains. Conclusion A major constituent in visible parts was Dioctyl phthalate and the yield of essential oils was . These extracts reveal in vitro antibacterial activity on the studied bacterial confirmed by the inhibition zone diameter ranging from 11 to 37 mm and a MIC value between and depending on the microorganism being tested. Keywords chemical composition antibacterial activity essential oils Launaea resedifolia 1.