Ahmed Akrout

Antioxidant and antitumor activities of Artemisia campestris and Thymelaea hirsuta from southern Tunisia.

The essential oil of Artemisia campestris and the ethanol-water, hexane and water extracts of A. campestris and Thymelaea hirsuta collected in southern of Tunisia were investigated for their antioxidant (DPPH, ABTS and beta-carotene methods) and antitumor growth inhibition of human colon cancer HT-29 cells using MTT test activities. All the A. campestris extracts tested at high concentrations (100 μg/ml) showed activity ranging from 19.5% for essential oil to 64.4% of negative control growth for infusion extract, except the hexane extract. With T. hirsuta, all the extracts tested (hexane and ethanol-water), except the infusion extract, also exhibited antitumor activity (58.2% and 65.5% of control growth respectively). The ethanol-water and infusion extracts of A. campestris showed higher antioxidant activity, polyphenol and flavonoid contents than those of T. hirsuta. These results show that there is a positive correlation between the antitumor activity and the antioxidant activity, and of these two activities and with the levels of polyphenols and flavonoids. The essential oil and the other extracts of A. campestris, which exhibited significant antitumor activity against the HT-29 cells deserve further research into the chemoprevention and treatment of colon cancer.

Composition and Intraspecific Chemical Variability of the Essential Oil from Artemisia herba‐alba Growing Wild in a Tunisian Arid Zone

The intraspecific chemical variability of essential oils (50 samples) isolated from the aerial parts of Artemisia herba‐alba Asso growing wild in the arid zone of Southeastern Tunisia was investigated. Analysis by GC (RI) and GC/MS allowed the identification of 54 essential oil components. The main compounds were β‐thujone and α‐thujone, followed by 1,8‐cineole, camphor, chrysanthenone, trans‐sabinyl acetate, trans‐pinocarveol, and borneol. Chemometric analysis (k‐means clustering and PCA) led to the partitioning into three groups. The composition of two thirds of the samples was dominated by α‐thujone or β‐thujone. Therefore, it could be expected that wild plants of A. herba‐alba randomly harvested in the area of Kirchaou and transplanted by local farmers for the cultivation in arid zones of Southern Tunisia produce an essential oil belonging to the α‐thujone/β‐thujone chemotype and containing also 1,8‐cineole, camphor, and trans‐sabinyl acetate at appreciable amounts.

The Essential Oil From Artemisia herba-alba Asso Cultivated in Arid Land (South Tunisia)

Abstract Seedlings of Artemisia herba-alba Asso collected from Kirchaou area were transplanted in an experimental garden near the Institut des Régions Arides of Médenine (Tunisia). During three years, the aerials parts were harvested (three levels of cutting, 25%, 50% and 75% of the plant), at full blossom and during the vegetative stage. The essential oil was isolated by hydrodistillation and its chemical composition was determined by GC(RI) and 13C-NMR. With respect to the quantity of vegetable material and the yield of hydrodistillation, it appears that the best results were obtained for plants cut at 50% of their height and during the full blossom. The chemical composition of the essential oil was dominated by β-thujone, α-thujone, 1,8-cineole, camphor and trans-sabinyl acetate, irrespective of the level of cutting and the period of harvest. It remains similar to that of plants growing wild in the same area.

Influence of drying time and process on Artemisia herba-alba Asso essential oil yield and composition

Abstract The essential oil content of Artemisia herba-alba Asso decreased along the drying period from 2.5 % to 1.8 %. Conversely, the composition of the essential oil was not qualitatively affected by the drying process. The same principle components were found in all essential analyzed such as α-thujone (13.0 – 22.7 %), β-thujone (18.0 – 25.0 %), camphor (8.6 - 13 %), 1,8-cineole (7.1 – 9.4 %), chrysanthenone (6.7 – 10.9 %), terpinen-4-ol (3.4 – 4.7 %). Quantitatively, during the air-drying process, the content of some components decreased slightly such as α-thujone (from 22.7 to 15.9 %) and 1,8-cineole (from 9.4 to 7.1 %), while the amount of other compounds increased such as chrysanthenone (from 6.7 to 10.9 %), borneol (from 0.8 to 1.5 %), germacrene-D (from 1.0 to 2.4 %) and spathulenol (from 0.8 to 1.5 %). The chemical composition of the oil was more affected by oven-drying the plant material at 35°C. α-Thujone and β-thujone decreased to 13.0 %and 18.0 %respectively, while the percentage of camphor, germacrene-D and spathulenol increased to 13.0 %, 5.5 %and 3.7 %, respectively.

Phenolic Contents, Antioxidant and Antimicrobial Potentials of Crithmum maritimum Cultivated in Tunisia Arid Zones

Abstract Polyphenols are bioactive molecules exhibiting a lot of scientific attention due to their multiple biological activities. The present study aimed at assessing the phenolic content, antibacterial activity and antioxidant activity of the different organs of Crithmum maritimum (leaves, flowers, seeds and stems) cultivated in the south east of Tunisia. The analyzed organs exhibited different content of total polyphenol (17.11 ± 0.77 to 9.42 ± 0.24 mg GAE g -1 DW) flavonoids (7.06 ± 0.18to 3.71 ± 0.1 mg EC g –1 DW) and tannins (5.24 ± to 1.06 ± 0.77 mg CE g –1 DW). However, seeds extracts displayed the highest DPPH• scavenging ability with the lowest IC50 value (406 ± 11 μg/ml) and for antibacterial activity is showed that the diameter of the largest inhibition (13 mm) is recorded for the extrat from stems of C. maritimum vis à vis a gram negative bacterium Pseudomonas aeruginos. The smaller diameter of inhibition (6 mm) was recorded for extract from seeds against gram-positive bacteria: Staphyloccus epidermidis.

Chemical and Biological Characteristics of Essential Oil of Rosmarinus officinalis Cultivated in Djerba

Abstract The essential oils extracted by Clavenger apparatus from leaves of Rosmarinus officinalis cultivated in different areas in Djerba (Island in the southern of Tunisia) were evaluated for their chemical composition (GC and GC-MS methods), antioxidant (DPPH method) and antibacterial activities (agar-well diffusion method). GC-MS analysis revealed the presence of three chemotypes of oils: 1,8-cineole, 1,8-cineole/camphor/α-pinene/camphene and 1,8-cineole/camphor/α-pinene/ verbenone/borneol which was not previously detected in Tunisian Rosmarinus officinalis. The three chemtypes exhibited moderate antioxidant activity with an IC50 ranged from 4.186 mg/ml for chemotype I to 7.298 for chemotype II and showed strong to moderate antibacterial activity against the six bacterial strains tested with a MIC ranged from 0.156 to 1.25 mg/mL (Chemotype I and chemotype II) and from 1.25 to 5 mg/mL (chemotype III). This study showed that the essential oil extracted from Rosmarinus officinalis cultivated in Djerba has similar chemical composition and biological activities as essential oil isolated from wild growing Rosmarinus officinalis.

Chemical Composition, Antioxidant and Antimicrobial Activities of Essential Oil from Crithmum maritimum Cultivated in Tunisia

Abstract Crithmum maritimum L., a species original from France and cultivated in Tunisia arid zones. In this study, we interested to the chemical composition and biological activities of essential oils from different parts of Crithmum maritimum L., . Theses oils were isolated by hydrodistillation and analyzed by GC and GC-MS. The antioxidant activity was evaluated by ABTS tests and the antibacterial activity was tested using the diffusion method. Yellow oils were obtained with yields ranging between 0.28 % and 3.60 %. Our results showed that essential oils of different plant parts were mainly composed by dillapiole (2.39 to 41.35 %), thymyl methyl ether (20.13 to 34.75 %), p-cymene (4.83 to 22.08 %) and γ-terpinene (22.54 to 43.29 %). Evaluation of antioxidant activity showed that the oils of flowers exhibited the most important antioxidant potential oils of flowers, leaves, seeds were the most active against Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus epidermidis, respectively. The essential oil of seeds was the most active against Staphylococcus aureus with an inhibition zone diameter of 18±0.5 mm. This study can contribute to provide useful data in understanding the impact of culture of Crithmum maritimum on chemical composition and biological effects of its essential oil and further studies should be conducted to achieve this goal.