Aicha Hassani

Extraction of essential oils from Algerian myrtle leaves using instant controlled pressure drop technology

In the present work, the new extraction process of Détente Instantanée Contrôlée DIC (French, for instant controlled pressure drop) was studied, developed, quantitatively and qualitatively compared to the conventional hydrodistillation method for the extraction of essential oils from Algerian myrtle leaves. DIC was used as a thermomechanical treatment, DIC subjecting the product to a high-pressure saturated steam. The DIC cycle ends with an abrupt pressure drop towards vacuum, and this instantly leads to an autovaporization of myrtle volatile compounds. An immediate condensation in the vacuum tank produced a micro-emulsion of water and essential oils. Thus, an ultra-rapid cooling of residual leaves occurred, precluding any thermal degradation. An experimental protocol was designed with 3 independent variables: saturated steam pressure between 0.1 and 0.6 MPa, resulting in a temperature between 100 and 160°C, a total thermal processing time between 19 and 221 s, and between 2 and 6 DIC cycles. The essential oils yield was defined as the main dependent variable. This direct extraction gave high yields and high quality essential oil, as revealed by composition and antioxidant activity (results not shown). After this treatment, the myrtle leaves were recovered and hydrodistilled in order to quantify the essential oil content in residual DIC-treated samples. Scanning electron microscope (SEM) showed some modification of the structure with a slight destruction of cell walls after DIC treatment.

Comparative study of essential oils extracted from Algerian Myrtus communis L. leaves using microwaves and hydrodistillation.

Two different extraction methods were used for a comparative study of Algerian Myrtle leaf essential oils: solvent-free-microwave-extraction (SFME) and conventional hydrodistillation (HD). Essential oils analyzed by GC and GC-MS presented 51 components constituting 97.71 and 97.39% of the total oils, respectively. Solvent-Free-Microwave-Extract Essential oils SFME-EO were richer in oxygenated compounds. Their major compounds were 1,8-cineole, followed by α-pinene as against α-pinene, followed by 1,8-cineole for HD. Their antimicrobial activity was investigated on 12 microorganisms. The antioxidant activities were studied with the 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging method. Generally, both essential oils showed high antimicrobial and weak antioxidant activities. Microstructure analyses were also undertaken on the solid residue of myrtle leaves by Scanning Electronic Microscopy (SEM); it showed that the SFME-cellular structure undergoes significant modifications compared to the conventional HD residual solid. Comparison between hydrodistillation and SFME presented numerous distinctions. Several advantages with SFME were observed: faster kinetics and higher efficiency with similar yields: 0.32% dry basis, in 30 min as against 180 min for HD.

Composition of Leaf, Fruit and Gall Essential Oils of Algerian Pistacia atlantica Desf.

Abstract Pistacia atlantica Desf. is widely distributed in South Algeria. It is a medicinal and foodstuff plant. Decoctions of leaves and fruits are used against stomach ache and caught. Ripe fruits are components of tonic sweets. Essential oils from leaves, fruits and galls of P. atlantica, analyzed by GC/FID, GC/MS and 13C-NMR, were dominated by monoter-pene hydrocarbons, α-pinene (32.6–54.7%) and β-pinene (8.0–20.2%) being the major components. Sesquiterpenes accounted for 14.1–21.7% in leaf oils, 3.6% in fruit oil and 4.8% in gall oil.

Composition and Chemical Variability of the Essential Oil from Pistacia lentiscus L. Growing Wild in Algeria Part I: Leaf Oil

Abstract The chemical composition of 17 samples of leaf oil from Pistacia lentiscus L. growing wild in Algeria was investigated by GC/FID (retention indices), GC/MS and 13C-NMR. Leaf oils were dominated by monoterpene hydrocarbons. α-Pinene (20.0–34.2%), myrcene (23.0–33.1%) or limonene (25.5–43.8%) were the major components. Statistical analysis of our results confirmed the chemical variability of the leaf oil of P. lentiscus and showed an atypical composition characterized by the pre-eminence of sesquiterpene hydrocarbons.

Determination of kinetic parameters of Phlomis bovei de Noé using thermogravimetric analysis

This paper reports the pyrolysis study of Phlomis bovei biomass by thermogravimetric experiments in order to determine the thermal degradation behavior and kinetic parameters. The weight losses were found to occur in three stages. In the DTG thermograms, an increase of the heating rate tended to delay thermal degradation processes towards higher temperatures. The average values of activation energy and pre-exponential factor calculated from Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose and Kissinger methods are 134.83, 134.06, 223.31kJ/mol and 4.1610(13), 1.1810(10), 2.8110(11)/s, respectively. The three-pseudo-component method shows that the activation energy increases with increasing the heating rate for hemicellulose and cellulose while the activation energy of the lignin decreased with an increase of the heating rate. Predicted results and experimental data exhibit similar tendencies and the three pseudo-components model with n different from unity 1 is recommended as the most suitable for prediction of kinetic behavior of Phlomis bovei de Noé.

Factor analysis and experimental design in high-performance liquid chromatography: XIII. Correspondence factor analysis of the heterogeneity of the behaviour of congeneric solutes series studied on homogeneous OV phases in gas chromatography

Abstract A correspondence factor analysis (CFA) of gas chromatographic retention data, i.e. , Kova´ts retention indices, is presented. The data matrix correspond to aromatic congeneric solutes series, monosubstituted benzenes, benzaldehydes or acetophenones, studied on the same type of stationary phases, namely phenylmethylsilicone with various percentages of the phenyl substituent (0–75%). CFA of three reduced submatrices gives a trend analysis of the relative behaviour of solutes and of the relative influence of stationary phases and temperatures. CFA was found to be a sensitive detector of the relative heterogeneity between solutes and/or chromatographic systems, even for the study of congeneric compound series studied on stationary phases of the same type.

Quantitative structure-retention relationships (QSRR) of congeneric aromatics series studied on phenyl OV phases in gas chromatography

Quantitative structure-retention relationships (QSRR) were established for three congeneric aromatic series of substituted benzene, benzaldehyde and acetophenone compounds which had been studied, previously, in gas chromatography, on six OV stationary phases with different phenyl percentages. Correspondence factor analysis (CFA) establishes the influences of temperature and phenyl percentage of the stationary phases on the retention indices. Topological analysis quantifies the contributions of molecular structure and phenyl content of the stationary phase on the chromatographic retention. The validity of the global linear model used in topological analysis is confirmed by CFA of the different set of topological parameters calculated for the retention of the compounds on the six OV stationary phases.

Analysis by Gas Chromatography-Mass Spectrometry of the Essential Oil of Rhamnus Alaternus L. (Rhamnaceae), an Aromatic and Medicinal Plant Growing in Algeria

Abstract The volatile constituents of the essential oil of Rhamnus alaternus L., growing in Algeria, extracted by hydro-distillation have been analysed. A total of 94 volatile compounds were identified and phytol (16.10 %), linalool (15.33 %) and (E)-β-damascenone (5.28 %) were the major components of the essential oil. This is the first report on the chemical compounds of the essential oil of this species.

Chemical Composition and Antioxidant Activity of Essential Oils from Algerian Daucus Carota L. subsp. carota Aerial Parts

Abstract The essential oil content and their chemical composition of aerial part, flowers, and both leaves and stems of wild carrot growing in Algeria (Daucuscarota L. ssp. Carota) as well as aerial part at different plant maturity stages was examined. The qualitative and quantitative analyses of the essential oils were performed using GC, GC-MS and 13C-NMR. 57 compounds were identified representing more than 85% of the total oil in each sample. Generally, The main components in the essential oil of aerial part in full flowering were α-pinene (21.3 %) and asarone (18.4 %), while the essential oils isolated from flowers and both leaves and stems were dominated by asarone (9.8, 9.4 %), α-pinene(10.9, 10.6 %) and β-bisabolene (7.6, 9.3 %) respectively. Before flowering and after flowering the major constituents were the linalool (11.2 %) and asarone (20.8 %) respectively. The antioxidant potential of the different essential oils was evaluated using the inhibition of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. All essential oils showed a relatively weak antioxidant capacity. The results obtained from the essential oils of the aerial part in full flowering 50 showed the strongest activity against DPPH than the other samples (IC =96,4±1.1 µg/ml).

Strategy of experimental design for intensification of solvent extraction of natural antioxidant flavonoids and phenols from buckthorn textured leaves

Abstract Prior to solvent extraction of plant-based active molecules, adequate texturing by Détente Instantanée Contrôlée (DIC; French for “Instant controlled pressure drop”) results in overcoming the slow diffusion of the solvent/solute through the solid matrix. This work aimed at determining the impact of DIC pretreatments on buckthorn (Rhamnus alaternus L.) morphology. DIC-operating parameters were selected as the saturated steam pressure, the thermal treatment time, and the number of cycles. A three-parameter five-level response surface method was used to optimize DIC processing parameters. Response factors were the overall and individual yields of flavonol aglycone extraction, and antioxidant activity of both expanded dried material (swell dried leaves) and extracts. The yield of flavonol aglycones was 18.23 mg Kaemp eq/g dry basis (mg Kaemp eq/g db) in 3 min for DIC-treated buckthorn, against 12.24 mg Kaemp eq/g db in 150 min for untreated natural buckthorn raw material. Furthermore, the antioxidant activity of DIC-treated material was exceptionally higher and the effectiveness of reducing power of DPPH radical was 68 times more than the untreated plant material.