Ismail Amri

Chemical composition, phytotoxic and antifungal activities of Pinus pinea essential oil

The chemical composition of essential oils isolated by hydrodistillation from the aerial parts of Tunisian Pinus pinea Linn. was analyzed by GC and GC/MS. Sixty-six compounds were identified, representing 98.5% of total oil, which was found to be rich in monoterpene hydrocarbons (73.1%) particularly limonene (54.1%), α-pinene (7.7%), and β-pinene (3.4%). The yield and the physico-chemical properties were determined. Results of the antifungal activity study by in vitro contact assay showed that P. pinea oil significantly inhibited the growth of ten plant pathogenic fungi. Moreover, herbicidal properties of the oil, tested on Sinapis arvensis L., Lolium rigidum Gaud., and Raphanus raphanistrum L., indicated that the oil completely inhibited the seed germination at a high concentration, while at low doses the oil acted by decreasing and delaying the germination and inhibiting the seedling growth of all tested weeds unlike the commercial herbicide. Our results showed that P. pinea essential oil could be valorized as bioproduct for biocontrol of weeds and fungal plant diseases.

Chemical composition, physico-chemical properties, antifungal and herbicidal activities of Pinus halepensis Miller essential oils

The chemical composition, physico-chemical properties, and antifungal and herbicidal activities of essential oils obtained by hydrodistillation from needles, stems and cones of Pinus halepensis Miller were investigated. The chemical composition analysed by GC and GC/MS varied significantly among organs. Among the 67 identified components, α-pinene (63% and 51.7%, respectively, in stems and cones) and (Z)-caryophyllene (33.9% in needles) were found to be the major ones. Moreover, it was found that chemical composition of essential oils extracted from different organs of P. halepensis Miller growing in Tunisia showed noteworthy differences with the same species cultivated in Algeria, Morocco, Greece and Italy based on a comparison with published results. In addition, the physico-chemical properties of essential oils from different organs of P. halepensis were analysed. The analysis of the refraction index, density and acid index of different oil samples showed a weak variability among organs. The in vitro antifungal activity of the essential oil samples evaluated against 10 cultivated crop fungi was found to be low, probably due to the low level of oxygenated compounds in P. halepensis oils. In contrast, the herbicidal activity investigated towards three common weeds in Tunisian cereal crops was very strong and seed germination was inhibited at 2 μl ml− 1. Thus, P. halepensis essential oil appears to have more value as a bioherbicide than as a biofungicide.

Comparative study of two coniferous species (Pinus pinaster Aiton and Cupressus sempervirens L. var. dupreziana [A. Camus] Silba) essential oils: chemical composition and biological activity

Maritime pine ( Pinus pinaster Aiton) and Saharan cypress ( Cupressus sempervirens L. var. dupreziana [A. Camus] Silba) are two cone-bearing seed coniferous woody plants. The chemical composition of their essential oils, isolated from needles and leaves by hydrodistillation, was analyzed with gas chromatography (GC) and gas chromatography mass spectrometry (GC/MS). A total of 66 and 28 compounds were identified, which represented 99.5% and 98.9% of total pine and cypress oils, respectively. Pinus pinaster oil was found to be rich in α-pinene (31.4%), (Z)-caryophyllene (28%), and α-humulene (6.7%); it was characterized by relatively high amounts of monoterpene and sesquiterpene hydrocarbons (44.5% and 46.3%, respectively). The major components identified in cypress oil were manoyl oxide (34.7%), α-pinene (31.8%), α-humulene (9%), and 6-3-carene (8.7%). Results of in vitro antifungal test assays showed that both oils significantly inhibit the growth of 10 plant pathogenic fungi. Herbicidal effects of the oils on seed germination, seed vigor, and seedling growth of three common crop weeds Sinapis arvensis L., Phalaris paradoxa L., and Raphanus raphanistrum L. were also determined; the oils completely inhibited seed germination and seedling growth of all the weeds.

Essential oil composition, phytotoxic and antifungal activities of Ruta chalepensis L. leaves from High Atlas Mountains (Morocco)

This study aimed at the determination of chemical composition of essential oil obtained by hydrodistillation, and to evaluate their phytotoxic and antifungal activities. Leaves of Ruta chalepensis L. were collected from the region of Tensift Al Haouz (High Atlas Mountains) Marrakech, Morocco. The essential oil (oil yield is 0.56%) was analysed by GC-FID and GC/MS. Twenty-two compounds were identified and accounted for 92.4% of the total oil composition. The major components were undecan-2-one (49.08%), nonan-2-one (33.15%), limonene (4.19%) and decanone (2.71%). Antifungal ability of essential oils was tested by disc agar diffusion against five plant pathogenic fungi: Fusarium proliferatum, Fusarium pseudograminearum, Fusarium culmorum, Fusarium graminearum and Fusarium polyphialidicum. The oils were also tested in vitro for herbicidal activity by determining their influence on the germination and the shoot and root growth of two weed species, Triticum durum and Phalaris canariensis L.

Chemical composition, phytotoxic and antifungal properties of Ruta chalepensis L. essential oils.

The chemical composition, and phytotoxic and antifungal activities of the essential oils isolated by using hydrodistillation from the aerial parts of Tunisian rue were evaluated. Significant variations were observed among harvest periods. The analysis of the chemical composition by gas chromatography/mass spectrometry showed that 2-undecanone (33.4–49.8%), 2-heptanol acetate (13.5–15.4%) and α-pinene (9.8–11.9%) were the main components. The antifungal ability of rue essential oils was tested by using disc agar diffusion against ten plant pathogenic fungi. A high antifungal activity was observed for the essential oil isolated at flowering developmental phase. Furthermore, rue essential oils showed high level of herbicidal activity against several weeds.

Activity antifungal of the essential oils; aqueous and ethanol extracts from Citrus aurantium L.

Our study is about the essential oil of Citrus aurantium L. in Tunisia and its plant extract. The yield of this essential oil is 0, 56% but the yield of the extract of plant was 17.1% for the aqueous extract ant 18.3% for the ethanolic extract. The analysis of chemical composition by using GC and GC/MS showed the essential oil of C. aurantium L. species to be rich in monoterpenes such as α-terpineol, lianolyl acetate, linalool and limonene. The antifungal activity of this oil showed us an inhibition of the germination of mushrooms, in the same way we could note that the biologic activities are generally assigned to the chemotypes high content in oxygenated monoterpene.

Essential oils as biological alternatives to protect date palm (Phoenix dactylifera L.) against Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae)

The aims of this research were to determine the chemical composition of the essential oil of three Tunisian plants and to evaluate their biological activity against eggs, larvae, and adult insects of Ectomyelois ceratoniae Zeller. The essential oils extracted from leaves of Thymus capitatus (L.) Hoffmanns. & Link, Rosmarinus officinalis L. and needles of Pinus halepensis Mill. were analyzed by gas chromatography-mass spectrometry; 34, 16, and 56 constituents were identified, respectively. The major constituents were (Z)-caryophyllene (23.8%), β-myrcene (20.5%) and α-pinene (13.3%) in P. halepensis oil, carvacrol (66.9%), p-cymene (9.1%), and δ-terpinene (6.2%) in T. capitatus oil and 1,8-cineole (47.5%), camphor (14.9%), α-pinene (14.1%), and borneol (13.1%) in R. officinalis oil. The insecticidal effects of essential oils on eggs, larvae, and adults of E. ceratoniae were investigated. Ovicidal activity of oils was studied by spray on eggs while larvicidal and adulticidal activities were assessed by fumigation and spray. Number of hatched eggs was verified after 10 d, larva and adult mortalities were observed after 6, 12, and 24 h. Globally, eggs and larvae were the most resistant to the three different oils, needing higher doses to obtain a higher mortality. The spray method was most effective than fumigation. Essential oil extracted from T. capitatus proved to be very toxic towards E. ceratoniae on all three phases at the dose of 20 μL mL-1 (100% inhibition), followed by the oil from R. officinalis (90-100% inhibition), nevertheless, weak activity was obtained with P. halepensis oil (68.3-85% inhibition). Results obtained may suggest that the essential oils of T. capitatus and R. officinalis possess high insecticidal activity and therefore, can be used in biotechnological application as natural preservative in stored dates and could be useful in managing populations of E. ceratoniae in field.

Chemical Composition and Herbicidal Effects of Essential Oils of Cymbopogon citratus (DC) Stapf, Eucalyptus cladocalyx, Origanum vulgare L and Artemisia absinthium L. cultivated in Morocco

Abstract This study is designed to examine the chemical composition of the hydrodistillated essential oils obtained from Cymbopogon citratus ( DC) Stapf, Eucalyptus cladocalyx, Origanum vulgare L, and Artemisia absinthium L. GC and GC-MS analysis of the four oils has shown a determination of 18 different components representing 89.3 % of the total oil for Cymbopogon citratus ( DC) Stapf that are neral (29.2 %) and geranial (18.2 %), followed by α-pinene (4.8 %) and myrcene (3.9 %) which are determined as the major compounds of the oil; for Eucalyptus cladocalyx oil there are 29 different components representing 79.0 % of the total oil, the major components are spathulenol (21.6 %) and 1,8-cineole (20.5 %), followed by p-cymene (15.1 %); for Origanum vulgare L. oil there are 25 different components representing 87.6 % of the total oil, the major components are carvacrol (34.0 %) and γ-terpinene (21.6 %), followed by p-cymene (9.4 %) and for Artemisia absinthium L. oil there are 26 different components representing 72.3 % of the total oil, which are determined as the major compounds of the oil. On the other hand, the four oils were experimented for their herbicidal activity against Sinapis avensis weed at different concentration then compared with commercial herbicides (2.4 D and glyophosate). The four essential oils have presented an interesting activities, the activity of C. citratus (DC) Stapf and E. cladocalyx have been evaluated as important. In the light of these findings, we suggested that the four essential oils may be considered as an interesting sources of bioherbicide components used as potent agents in weeds control.