Ridha El Mokni

Chemical composition and antioxidant activity of essential oil from aerial parts of Teucrium flavum L. subsp. flavum growing spontaneously in Tunisia

The objectives of this study were to chemically characterise and evaluate the antioxidant potential of the essential oil from Teucrium flavum L. subsp. flavum growing spontaneously in Tunisia. The volatile oil was extracted by hydrodistillation of the aerial parts in a Clevenger type apparatus. Forty constituents were identified via GC and GC-MS analysis. β-caryophyllene (32.5%) and α-humulene (17.8%) were the most abundant components. The evaluation of free radical scavenging activity using stable DPPH free radical showed that the volatile oil exhibits a moderate antioxidant activity and reduces DPPH to 50% at EC50 value of 1230 μg mL− 1.

New bioactive labdane diterpenoids from Marrubium aschersonii

Abstract A phytochemical investigation of the ethanol extract of Marrubium aschersonii Magnus (Lamiaceae) collected from Tunisia led to the isolation and identification of two new labdane diterpenoids, marrubaschs A (1) and B (2), along with two known compounds (3 and 4). Their structures were elucidated by spectroscopic methods including HRESIMS and NMR techniques. All compounds were evaluated for their inhibitory effects on the nitric oxide (NO) production induced by lipopolysaccharide in RAW 264.7 macrophage cells. Compound 2 exhibited weak inhibition of NO production with an IC50 value of 35 ± 1.0 μM.

Comparative study on the chemical constituents of essential oils from different organs of the Sicilian Kundmannia (Kundmannia sicula L.) DC. (Apiaceae) growing spontaneously in Tunisia

Essential oils from odorous and volatile compounds possessing several therapeutic benefits are considered of a paramount importance in everyday human life. This study deals with a comparative study of essential oils from different parts of an aromatic plant Kundmannia sicula (L.) DC. (Apiaceae) growing in Tunisia. The hydro-distilled essential oils of the leaves and inflorescences with mature seeds (IMS) of K. sicula were analysed for the first time by gas chromatography equipped with flame ionisation detector and gas chromatography coupled with mass spectrometry. Fifty leaves and 47 IMS constituents were identified, accounting for 97.9% and 98.2% of the total oil, respectively. The major compounds identified from the leaves and IMS oils were isocurcumenol (9.9–10.1%), hexadecanoic acid (9.5–10.9%), spathulenol (6.9–3.4%), 10-epi-γ-eudesmol (6.3–5.5%), α-cubebene (5.9–6.1%) and trans-dihydro occidentalol (52–6.6%). The essential oil consists mainly of oxygenated monoterpenes (50.7–53.2%).

Extraction of carotenoids from Lycium ferocissimum fruits for cotton dyeing: Optimization survey based on a central composite design method

Studies were carried out to assess the extraction yield of carotenoids from the African boxthorn (Lycium ferocissimum Miers, Solanaceae) fruits with different solvents and solvent mixtures, to optimize the extraction conditions for maximum recovery and to improve the extraction efficiency. Among other solvents, a mixture of hexane and acetone gave the highest carotenoid extraction. Extraction conditions, such as hexane percentage in hexane/acetone solvent mixture, solvent-solid ratio, and extraction time were optimized using a statistically designed experiment. A regression equation for predicting the carotenoid yield as a function of three extraction variables was derived by statistical analysis. The optimized conditions for maximum carotenoids yield were 45 % hexane in solvent mixture, solvent-solid ratio of 70 (ml/g) and extraction time 70 min. The dyeability of cotton with carotenoids extract has also been studied. Unmordant and postmordanted bleached cotton fabric with alum and ferrous sulphatewas dyed. Color measurements and fastness properties as light, rubbing and wash were tested.

Chorological and taxonomic notes on African plants

Abstract The taxonomy of complicated native African taxa, Biscutella maritima (Brassicaceae) and annual species of Sesuvium (Aizoaceae) is discussed. The distribution of B. maritima is widened to the most of the coastal areas of NE Algeria and N Tunisia. Morphological differences with regard to other North African members of Biscutella ser. Biscutella are reported to facilitate the identification of B. maritima. We propose to accept four annual Sesuvium species (instead of the one previously accepted species, S. sesuvioides sensu amplissimo) with different distributions in Africa: S. digynum, S. hydaspicum, S. sesuvioides s.str. and S. nyasicum. A delimitation key based on morphological and carpological characters is provided. Lectotypes of S. digynum, S. digynum var. angustifolium, S. hydaspicum, S. nyasicum, Diplochonium sesuvioides (Sesuvium sesuvioides) and Trianthema polysperma (synonym of Sesuvium hydaspicum) are selected. Other discussed taxa belong to the alien elements of the flora. Atriplex semibaccata (Amaranthaceae-Chenopodiaceae) is reported as a new species for Cape Verde. Gaillardia × grandiflora (Asteraceae) is discovered as a new species for Africa found in Morocco. Prosopis velutina (Fabaceae) is collected for the first time in Northern Africa (Morocco). Mollugo verticillata (Molluginaceae) is recorded as a new species for DR Congo. Its morphology, including seed ornamentation, is discussed in reference to other similar-looking Molluginaceae. Incidence of American species Heterotheca subaxillaris (Asteraceae) in North Africa is discussed. Vernonanthura polyanthes (Asteraceae) is recorded as a naturalized invasive species in eastern Zimbabwe. It seems to be the first documented discovery of this ergasiophyte in Africa.

Effects of different ecological conditions and extraction techniques on the quality of volatile oils from flaxleaf fleabane ( Erigeron bonariensis L.)

The objective of this study was mainly to compare the chemical composition of essential oils from the whole parts of Erigeron bonariensis obtained by traditional hydrodistillation technique and by supercritical fluid extraction recognized as an alternative efficient method. A comparison of the effects of different ecological conditions on the chemical composition of essential oil samples collected in different localities, Monastir (Tunisia) and Cagliari (Sardinia, Italy), has been also performed. Thus, interestingly gas chromatography/mass spectrometry (GC/MS) analysis showed that the volatile fraction prepared by supercritical fluid extraction from Tunisian E. bonariensis was richer in terpenes components (90.6%) compared with the essential oil obtained by traditional hydrodistillation (86.2%). Chemical analysis revealed that although roughly the same compounds were extracted using both supercritical fluid extraction (SFE) and hydrodistillation (HD) but with different percentages. Furthermore, the essential oil of Tunisian E. bonariensis obtained by traditional hydrodistillation has high content of caryophyllene oxide (18.7%), spathulenol (18.6%) and α-curcumene (10.2%) whereas Sardinian essential oil was richer in Cis-lanchnophyllum ester (14.2%) and (E)-β-farnesene (12.0%). Key words: Erigeron bonariensis L., essential oils, supercritical carbon dioxide extraction, chemical composition, gas chromatography/mass spectrometry (GC/MS).

Volatile Profile of Herniaria fontanesii Growing Spontaneously in Tunisia

The essential oil extracted from Desfontaines rupturewort, Herniaria fontanesii J. Gay subsp. fontanesii growing wildly in Tunisia, was analyzed using GC and GC-MS techniques. The free radical scavenging capacity and total phenol contents of three crude extracts having different polarities (n-hexane, ethyl acetate and methanol) were examined. Thus, a total of 35 constituents were identified in the Desfontaines rupturewort essential oil representing 89.8% of the whole constituents. The oil was dominated by hexadecanoic acid, caryophyllene oxide, terpin-4-ol, khusimone and trans-sabinene hydrate. The total phenolic contents ranged from 16.91 to 92.27 mg of gallic acid/g of dry weight and they were found to be significantly higher in methanol than in polar ethyl acetate and hexane extracts. Correlations were observed between the phenolic contents and the antioxidant properties. Thus, the antioxidant activity of the methanol extract was superior to that of all samples tested (IC50 = 0.21 ± 0.04 mg/mL).

Chemical Variability of Two Essential Oils of Tunisian Rue: Ruta montana and Ruta chalepensis

Abstract: The genus Ruta includes some popular aromatic species of the flora of Tunisia, with important medicinal properties. They have been traditionally been used in the folk as herbal remedy medicine for the treatment of a variety of disorders. Information about the essential oil compositions of the Tunisian medicinal plant Ruta montana has not been reported. For this reason the objective of this study was to determine and compare the chemical composition of the essential oils of dried leaves and stems of the two principal Tunisian Ruta species: Ruta montana and Ruta chalepensis. Chemical analyses were performed by GC-MS assays. Essential oil yields was 0.66 %, its the same for all organs. For the chemical composition, independent of species and organs, the major compound for the 4 essential oil was the 2-undecanone. 1-nonene and 2-nonanone were the second major component in R. montana and R. chalepensis essntial oils.

A new addition to the alien flora of Tunisia, Amaranthus spinosus L. (Amaranthaceae s.l.), with notes on A. diacanthus Raf.

Abstract Amaranthus spinosus L. (Amaranthaceae s.l.), a species native to the Neotropics, has been found in four localities (Bizerta, Bir Bouregba, Hammamet, and Nabeul) of N. Tunisia. Our discovery represents the first record at national level, and the second one for N. Africa. Morphological characters and ecological data are given. Nomenclatural notes are provided for the name A. diacanthus, which was regarded by some authors as heterotypic synonym of A. spinosus. A neotype is designated in the present paper based on a specimen preserved at LSU.

Angeloylated Germacranolides from Daucus virgatus and Their Plasmodium Transmission Blocking Activity

Phytochemical investigation of the aerial parts of the Tunisian plant Daucus virgatus led to the isolation of eight new germacranolides named daucovirgolides A-H (1-8). The stereostructures of these sesquiterpene lactones, decorated by either one or two angeloyl groups, have been determined by a combination of MS, NMR spectroscopy, chemical derivatization, and comparison of experimental electronic circular dichroism curves with TDDFT-predicted data. Daucovirgolide G (7) proved to be the single member of this family to possess a marked inhibitory activity (92% at 50 μg/mL) on the development of Plasmodium early sporogonic stages, the nonpathogenic transmissible stages of malaria parasites, devoid of general cytotoxicity. The selective activity of daucovirgolide G points to the existence of strict structural requirements for this transmission-blocking activity and therefore of a well-defined, although yet unidentified, biological target.