Mehrez Romdhane - Academia.edu (original) (raw)

Papers by Mehrez Romdhane

Biochemical Systematics and Ecology, 2006

The yield and composition variation of the essential oil from Thymus capitatus Hoffmanns. et Link... more The yield and composition variation of the essential oil from Thymus capitatus Hoffmanns. et Link., an aromatic plant which grows in the wild state in the area of Korba (Tunisian Cap Bon) were determined. Essential oil was obtained by steam distillation apparatus at atmospheric pressure. The yield in essential oil showed a maximum at the flowering stage (1.08-2%) and a minimum during the dormancy period (about 0.2%). Analysis was performed by GC and GC-MS. The composition also showed different patterns at different phases of the vegetative cycle. At the flowering period the essential oil is rich in carvacrol. p-Cymene showed a variation with a maximum at the minimum of carvacrol.

Journal of The Energy Institute, Oct 1, 2023

Fish & Shellfish Immunology, Jul 1, 2023

Bioenergy Research, Feb 22, 2022

L'extraction de principes actifs ou d'huiles essentielles a partir de substrats vegetaux ... more L'extraction de principes actifs ou d'huiles essentielles a partir de substrats vegetaux a l'aide d'un solvant approprie est une operation unitaire classique du genie chimique. L'objectif de ce travail est double: demontrer la faisabilite d'un mode d'extraction en continu a contre-courant dans une colonne mecaniquement agitee et ameliorer le rendement/la selectivite de l'extraction par une activation ultrasonore. Dans certains cas, les ultrasons permettent notamment d'accelerer la cinetique en augmentant la diffusion intraparticulaire du solute recherche, qui est l'etape limitante au transfert. Trois extractions differentes ont ete envisagees: pyrethrines a partir de fleurs de pyrethre, huile a partir de graines de pastel, hemicelluloses a partir de coques de tournesol. Les 2 premieres sont effectuees a l'hexane, la derniere en solution aqueuse a ph controle. Dans chacun des cas, l'extraction sous ultrasons a ete etudiee. Les resultats obtenus ont suscite une recherche de nature fondamentale, visant a expliciter les mecanismes de propagation ultrasonore dans divers reacteurs. A ce titre, il a fallu developper un capteur approprie, apte a enregistrer les effets locaux des ultrasons. Correles a la puissance localement disponible: une sonde thermoelectrique a ete retenue. Le principe de la mesure est fonde sur l'echauffement d'une matiere absorbante (silicone) detecte par un thermocouple. Un modele thermique decrivant la dissipation dans la matiere a ete ecrit pour interpreter les resultats experimentaux. Cette technique a permis de comparer differentes geometries de reacteurs ultrasonores, de mettre en evidence l'influence de l'agitation et de la presence de particules solides sur la repartition des ultrasons dans le volume reactionnel

Journal of Food Science, Sep 1, 2009

Toulouse Archive Ouverte (OATAO) OATAO is an open access repository that collects the work of Tou... more Toulouse Archive Ouverte (OATAO) OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible.

African Journal of Biotechnology, Apr 30, 2023

Six wild populations of Nitraria retusa growing in Tunisia (Mehdia, Mtorech, Kataena, Matmata, Be... more Six wild populations of Nitraria retusa growing in Tunisia (Mehdia, Mtorech, Kataena, Matmata, Bechima, and Tataouine) were evaluated for their mineral contents, phytochemical composition, phenols content and antioxidants activity. The preliminary phytochemical composition revealed the presence of phenolic compounds such as flavonoids, sterols terpenes and free quinones. Analysis of mineral composition showed the poverty of N. retusa populations in K, Mg and Ca. The levels of polyphenols were important, they varied from 107.497 ± 7.97 to 186.64 ± 17.56 mg EAG/g DW among populations of Ketaena and Mtorech, respectively. The levels of flavonoids vary from 25.63±3.61 to 42.59±1.57 mg ER/g DW. Good antioxidant activities were revealed by the DPPH test. The population of Mahdia showed the highest antioxidant activity (IC 50 =1.64±1.42 µg/ml). The principal components analysis performed on the different parameters for the 6 N. retusa populations analyzed revealed that population structure was clearly isolated and subdivided into four distinct groups not according to bioclimate.

Acta Ecologica Sinica, Apr 1, 2021

There is a growing request to find an effective method of polyphenols extraction from agro-indust... more There is a growing request to find an effective method of polyphenols extraction from agro-industry by-product as pomegranate. In this study, response surface methodology (RSM) was used to explore the effect of three factors on ultrasonic assisted extraction (UAE) of total polyphenols (TP), total flavonoids (TF) and condensed tannins (CT) from pomegranate peels. The optimal conditions were determined for each phenolic compound using regression model equations and 3-D plots. The high TP, TF and CT content were obtained with, respectively, liquid/solid ratio of 20.00, 9.77, 9.77, extraction time of 36.38, 41.82, 30.39 min and 36.00, 83.64, 59.26% of ethanol percentage. In fact, liquid/solid ratio of 20, extraction time of 30.94 min and 59.26% of ethanol gives the highest contents of TP, TF and CT simultaneously. The experimental values using optimal conditions agreed with the predicted values. The pomegranate peels extract obtained under optimum conditions have an effective antioxidant activity as determined by ABTS and DPPH assays.

Food Science and Technology International, Mar 1, 2018

The current study deals with an innovation in the hot air convective drying process consisting of... more The current study deals with an innovation in the hot air convective drying process consisting of the application of two consecutive drying steps. Temperatures ranging between 60 and 80 C for times between 200 and 600 s were applied for the first stage, and from 40 to 80 C for the second stage. Salvia officinalis, an aromatic, medicinal Mediterranean plant with remarkable antioxidant properties, was selected for this study. A management of the process regarding the antioxidant capacity of S. officinalis extracts and energy consumption was carried out: (i) artificial neural networks were applied to model the evolution of the antioxidant capacity and moisture content of the product in the drying process; (ii) a genetic algorithm and a multiobjective genetic algorithm were selected to optimize the drying process, considering the antioxidant capacity and/or the energy consumption in the objective function. The results showed that the optimum values depended, logically, on the controllable variables values (hot air temperatures and drying times), but also on the uncontrollable variable values (room air temperature and relative humidity and the product's initial mass and moisture content).

Chemistry Africa, May 11, 2023

Life, Mar 29, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Journal of Essential Oil Research, Dec 3, 2021

Flos Chrysanthemi indici, an important medicinal and aromatic plant in China, is considered to ha... more Flos Chrysanthemi indici, an important medicinal and aromatic plant in China, is considered to have many different preservative and pharmacological properties. Considering the capability of essential oils (EOs), the present study is conducted to compare different extraction methods in order to improve yield and biological activities. Hydro-distillation (HD), steam-distillation (SD), solvent-free microwave extraction (SFME), and supercritical fluid extraction (SFE) are employed to prepare EOs from Flos Chrysanthemi indici. A total of 71 compounds are assigned by gas chromatography/mass spectrometry (GC-MS) in comparison with retention indices. These include 32 (HD), 16 (SD), 31 (SFME) and 38 (SFE) compounds. Major constituents of EOs differ according to the extraction methods were heptenol, tricosane, camphor, borneol, and eucalyptol. EOs extracted by SFME exhibit higher antioxidant activity. All EOs show varying degrees of antimicrobial activity, with minimum inhibitory concentration (MIC) ranging from 0.0625 to 0.125 mg/mL and SFME and SFE prove to be efficient extraction methods. EOs alter the hyphal morphology of Alternaria alternata, with visible bumps forming on the mycelium. Overall, these results indicate that the extraction method can significantly influence the composition and biological activity of EOs and SFME and SFE are outstanding methods to extract EOs with high yield and antimicrobial activity.

Notulae Botanicae Horti Agrobotanici Cluj-napoca, Dec 22, 2020

Essential oil (EO) of Laurus nobilis, from Tunisian, France and Austrian were screened for their ... more Essential oil (EO) of Laurus nobilis, from Tunisian, France and Austrian were screened for their chemical composition, antioxidant and antimicrobial activities and compared. GC-MS analysis showed that leaves of Tunisian L. nobilis had camphor (34.43%), 1,8-cineole (20.21%) and α-terpineol (7%) as major components. France and Austrian EOs had a high content of 1,8-cineole (45.8% and 43.4%, respectively) followed by bornyl acetate (13.8% and 17.7% respectively) and methyl eugenol (7.7% and 10.9% respectively). Antioxidant potential was measured by ABTS and DPPH tests. Tunisian L. nobilis EO showed greater radical scavenging by ABTS activity (IC50=44.8±0.1 mg/L) than the France and Austrian EOs (76.4±3.2 mg/L and 81.4±4.0 mg/L, respectively). However, for DPPH test system, French and Austrian EOs activities were excellent (IC50=176.1±5.1 mg/L and 236.3±2.9 mg/L respectively) then Tunisian L. nobilis EO (IC50=2859.7±99.0 mg/L). A good Antimicrobial activity was observed on the yeasts and fungi for all EOs. Tunisian laurel EO show a better antibacterial activity against gram-negative bacteria (Klebsiella pneumonial, E. coli and Salmonella enterica CMI: 0.004 mg/ml) than gram-positive ones (Bacilus subtilis, Staphylococcus aureus and Listeria monocytogenes CMI: 0.01 mg/ml). A significant antifungal activity of Tunisian EO was also observed against fungi and yeasts species (CMI: 0.004 mg/ml). France essential oil shows better activities against all organisms tested wail Austrian oil activity is more important against yeasts species tested and Mucor ramannianus (fungi). Chemical composition, antimicrobial and antioxidant activity of Tunisian L. nobilis essential oil, were different from that of France and Austrian and it give the opportunity for its uses in new pharmaceuticals and natural therapies of infectious diseases.

Natural Product Research, Oct 1, 2013

In this study, supercritical fluid extraction (SFE) with CO2 and hydrodistillation (HD) were comp... more In this study, supercritical fluid extraction (SFE) with CO2 and hydrodistillation (HD) were compared as methods to isolate the essential oil from Cupressus sempervirens. The odour of the oil obtained by SFE at 90 bar and 40°C was very close to the odour of the leaves of C. sempervirens before the extraction. Compounds extracted by both SFE and HD were identified by GC-FID and GC-MS. Moreover, the difference in the chemical composition obtained by SFE and HD was quite noticeable qualitatively and quantitatively. Phenolic composition and antioxidant activity were also determined. Compared to HD, the SFE method presents some advantages: the extraction was completed after 1 h in SFE, although 4 h is necessary for HD, and the yield was improved by 34%. Finally, it has also been shown that SFE is very selective towards some specific components such as manoyl oxide, trans-totarol and α-acoradiene.

Food Chemistry, Dec 1, 2013

In the present study, three techniques of extraction: hydrodistillation (HD), solvent extraction ... more In the present study, three techniques of extraction: hydrodistillation (HD), solvent extraction (conventional 'Soxhlet' technique) and an innovative technique, i.e., the supercritical fluid extraction (SFE), were applied to ground Tetraclinis articulata leaves and compared for extraction duration, extraction yield, and chemical composition of the extracts as well as their antioxidant activities. The extracts were analyzed by GC-FID and GC-MS. The antioxidant activity was measured using two methods: ABTS + and DPPH. The yield obtained using HD, SFE, hexane and ethanol Soxhlet extractions were found to be 0.6, 1.6, 40.4 and 21.2-27.4 g/kg respectively. An original result of this study is that the best antioxidant activity was obtained with an SFE extract (41 mg/L). The SFE method offers some noteworthy advantages over traditional alternatives, such as shorter extraction times, low environmental impact, and a clean, non-thermally-degraded final product. Also, a good correlation between the phenolic contents and the antioxidant activity was observed with extracts obtained by SFE at 9 MPa.

Lawsonia inermis flowers were evaluated for chemical and biological properties for the first time... more Lawsonia inermis flowers were evaluated for chemical and biological properties for the first time. Extracts were prepared successively by hexane, chloroform and methanol. Phenolics (7.8-239.0g gallic acid equivalent/kg of dry mass), tannins (12.5-148.5mg cathechin equivalent/kg of dry mass) and flavonoids (36.2-43.75mg quercetin equivalent/kg of dry mass) were quantified. Methanol extract has a high antioxidant activity (IC 50 =8.5mg/L by DPPH assay and IC 50 =5mg/L by ABTS assay) and a good anti-inflammatory activity against 5-Lipoxygenase (IC 50 =49.33mg/L) compared to references. However, extracts exhibited a poor anti-Alzheimer and antidiabetic activities. Chloroform extract exhibited a higher anticancer activity (IC 50 =20mg/L). We observed high correlations between phenolics and flavonoids with antioxidant and anti-inflammatory activities (0.75<R2<0.97). Finally, a very good correlation between anti-inflammatory activity and antioxidant activity with R2=0.99. It may be interpreted that the greatest anti-inflammatory activity was excreted by the best antioxidants extracts, which contain the high amounts of total phenolics.

Chemistry & Biodiversity, Jul 17, 2023

Phytochemical screening of aqueous extract from six medicinal wild plants grown in South‐eastern ... more Phytochemical screening of aqueous extract from six medicinal wild plants grown in South‐eastern of Tunisia: Atriplex halimus, Teucrium polium, Moricandia arvensis, Deverra tortuoa, Haplophyllum tuberculatum and Polygonum equisetiforme were evaluated. Both decoction and ultrasound assisted extraction were used. Antioxidant, antibacterial proprieties, and phenolic profiling, using LC‐ESI‐MS method, were assessed. Total polyphenols, flavonoids, and condensed tannins contents ranged from 7.47±0.19 to 22.25±0.49 mg GAE/g Dw, 5.47±0.06 to 7.55±0.07 mg RE/g Dw, and 0.33±0.02 to 19.43±0.64 mg TAE/g Dw, respectively. Moreover, the reducing power and DPPH tests showed that P. equisetiforme (EC50: 12.50±0.50 μg/ml; DPPH⋅+: 213.49±4.24 mg TEAC/g DW), T. polium (EC50: 25.00±1.00 μg/ml; DPPH⋅+: 181.39±9.47 mg TEAC/g DW) as well as H. tuberculatum (EC50: 56.25±0.25 μg/ml; DPPH⋅+: 177.83±5.85 mg TEAC/g DW) extracts were the most effective natural antioxidants. For anti‐bacterial activity, the ultrasonic extract of H. tuberculatum showed the highest activity against both P. aeruginosa (13.50±0.71 mm) and S. aureus (13.00±0.00 mm) at 10 mg/ml. Furthermore 24 phenolic compounds were identified, with predominance of quinic acid, gallic acid, protocatechuic acid, syringic acid, p‐coumaric acid, trans‐ferulic acid, catechin (+), trans‐cinnamic and silymarin. These results were further consolidated by to heatmap clustering with P. equisetiforme, H. tuberculatum, T. polium as the main antioxidant and antibacterial sources which supports their domestication and industrial use.

Notulae Scientia Biologicae

Eucalyptus has become one of the most widely planted genera in the world because of its tolerance... more Eucalyptus has become one of the most widely planted genera in the world because of its tolerance to a wide range of soil types and climates, as well as for its many industrial, commercial and medicinal uses. Eucalyptus torquata Luehm. is a plantation species frequently planted in semi-arid and arid regions for its ecological, forestry, ornamental and melliferous interests. Based on literature, drought tolerance of this species was mostly directed to adaptation mechanisms. Physiological investigations reveal the importance of stomatal closure and increased solute contents suggesting that osmotic adjustment is one of the main responses to drought in E. torquata. On the other hand, it showed low sensitivity to salt stress. This paper also highlights the immense benefits of E. torquata which contains essential oils with variable chemical composition and rich essentially in 1,8-cineole, torquatone, α-pinene, trans-myrtanol, α-eudesmol, β-eudesmol, globulol, trans-pinocarveol and aromade...

Journal of Food Science, 2010

Une approche de la valorisation des huiles essentielle d'Eucalyptus gracilis a ete effectuee.... more Une approche de la valorisation des huiles essentielle d'Eucalyptus gracilis a ete effectuee. Les huiles essentielles extraites par hydrodistillation et par entrainement a la vapeur ont ete identifiees par chromatographies en phase gazeuse et couplee a la spectrometrie de masse. Cette etude a montre que, le rendement en huile essentielle de la plante varie d'un mois a un autre et que le meilleur est enregistre au mois de Fevrier (5.36 %), correspondant a la periode de floraison. L'etude qualitative a montre que, les composes identifies et leurs proportions varient d'une periode a une autre. Parmi un total de 22 composes differents identifies au cours de l'etude, seuls le 1,8-cineole, l' α-pinene, 1' α-terpineol, l'isopinocarveol et le trans-pinocarveol, sont majoritaires et presents dans toutes les huiles essentielles avec des proportions relatives variables.