No abstract

Asteriscus graveolens is an endemic medicinal plant mainly distributed in south-western Algeria and south-eastern Morocco. The essential oils of leaves, stems, and flowers of A. graveolens had been studied by GC, GC/MS, and (13) C-NMR. The spectral data of two nerolidol derivatives, 6-oxo- and 6-hydroxycyclonerolidol, were reassigned by 1D- and 2D-NMR spectroscopy. These compounds can be considered as chemical markers of this genus. The structure of a monoterpenic diester with a chrysanthenane skeleton, i.e., cis-8-acetoxychrysanthenyl acetate, was determined for the first time on the basis of GC/MS, and 1D- and 2D-NMR. The stem and leaf oils were characterized by high content of oxygenated sesquiterpenes with 6-oxo- and 6-hydroxycyclonerolidol as major components, and the flower essential oils were dominated by the new monoterpenic compound cis-8-acetoxychrysanthenyl acetate.

The aim of the present study is to investigate the chemical composition, antibacterial and antioxidant activities of three essential oils extracted by hydrodistillation from the aerial parts of Artemisia arborescens L., which was collected from three different regions near Tlemcen city in the West Northern of Algeria: Beni Snous, Bidar and Chetouane. The chemical composition was investigated using both capillary gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) techniques. Fifty-two compounds were detected, a total of fifty compounds, representing 81.8 to 90.2% of the total oils were identified in the three samples of essential oils. The essential oils of A. arborescens were rich in camphor (Beni Snous: 72.2%, Bidar: 50.3% and Chetouane: 32.8%). The present composition of the essential oils, with camphor as the only most abundant component, was considered as a new chemotype of A. arborescens growing in West Northern of Algeria. Antibacterial activity of the essential oils against gram-positive and gram-negative bacteria, was tested using the diffusion method and by determining the inhibition zone. The results showed that the oils had a great potential antibacterial activity against some bacteria. The maximum zone of inhibition was obtained against Enterococcus faecalis (22 mm). In contrast, the oils were ineffective on the inactivation of Lysteria monocytogenes and Escherichia coli. Antioxidant capacity was assessed by in vitro tests using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and significant activity was found for these A. arborescens oils.