Malika Trabelsi-Ayadi

Detailed Polyphenol and Tannin Composition and Its Variability in Tunisian Dates (Phoenix dactylifera L.) at Different Maturity Stages

The polyphenol profile of two Tunisian varieties of dates including flavanols, flavonols, flavones, and hydroxycinnamates was characterized. Three tissue zones (flesh, peel, and stone) and three maturity stages were considered. Phenolic compounds were analyzed using reversed phase high-performance liquid chromatography coupled to UV-visible and electrospray mass spectrometry. Procyanidin oligomers and polymers were characterized and quantified using phloroglucinolysis prior to HPLC analysis. Procyanidin polymers based on (-)-epicatechin structure were by far the most concentrated polyphenols in ripe dates, accounting for 95% of total polyphenols with an average concentration of 14 g/kg in the fresh edible parts of the fruit. Interestingly, procyanidins were also highly concentrated in the stones. The concentration and average degree of polymerization (DPn) of the procyanidins decreased according to maturity. Other phenolics, including caffeoylshikimic acid hexoside, caffeoyl-sinapoyl monohexoside and dihexoside, and acetylated flavonols, were tentatively identified for the first time in the fruit.

Simultaneous detection of antibiotics and other drug residues in the dissolved and particulate phases of water by an off-line SPE combined with on-line SPE-LC-MS/MS: Method development and application.

Due to their widespread use in human and animal healthcare, antibiotics and other drug residues are ubiquitous in the aquatic environment. Given their potential impacts on ecosystem functioning and public health, the quantification of environmental drug residues has become a necessity. Various analysis techniques have been found to be suitable for reliable detection of such compounds. However, quantification can be difficult because these compounds are present at trace or ultra-trace levels. Consequently, the accuracy of environmental analyses depends on both the efficiency and the robustness of the extraction and quantification method. In this work, an off-line solid-phase extraction (SPE) combined with on-line SPE-LC-MS/MS was applied to the simultaneous extraction and quantification of 26 pharmaceutical products, including 18 antibiotics, dissolved in a water phase. Optimal conditions were determined and then applied to assess the contamination level of the targeted drug residues in water collected from four sites in Northern France: a river, the input and output of an aerated lagoon, and a wastewater treatment plant. Drug residues associated with suspended solid matter (SSM) were also quantified in this work using pressurized liquid extraction (PLE) combined with an on-line SPE-LC-MS/MS system in order to complete an assessment of the degree of total background pollution.

Preparation and structure of HGdP2O7.3H2O

Single crystal structure of HGdP2O7·3H2O has been solved, for the first time, using 2344 X-ray reflections with a final R value: 0.029. This salt crystallizes in the triclinic system; the space group is P1, with Z = 2 and the following unit-cell dimensions: a=6.4585(4) b=6.976(1) c=9.803(1) A α=98.48(1) β=99.439(8) γ=88.388(9)° V=430.93(9) A3 The atomic arrangement of HGdP2O7·3H2O is built by pairs of HP2O73- anions interconnected by strong hydrogen bonds and located around the inversion center at (0, 0, 1/2). The cohesion between these entities is provided by GdO8 polyhedra.

Phenolic Profile of Tunisian Opuntia Ficus Indica Thornless form Flowers via Chromatographic and Spectral Analysis by Reversed Phase-High Performance Liquid Chromatography-UV-Photodiode Array and Electrospray Ionization-Mass Spectrometer

The qualitative and quantitative analysis of phenolic compounds of the methanol extract of Tunisian thornless form Opuntia ficus indica flowers was described. Reversed phase high-performance liquid chromatography UV photodiode array analysis detected four peaks at 320 nm, attributed to phenolic acids; three of them were quantified to 141 mg.kg−1 of fresh plant material. Electrospray ionization mass spectrometer analysis detected 8 glycosylated flavonols at 350 nm, identified among 11 chromatographic peaks. The amount of flavonoids was 4980 mg.kg−1 of fresh plant material, with isorhamnetin glycosylated derivatives as the main flavonoid components (55.1%), quercetin derivatives as the second (23.7%), and kaempferol derivatives as the third (8.4%).

Supercritical SC-CO2 and Soxhlet n-Hexane Extract of Tunisian Opuntia ficus indica Seeds and Fatty Acids Analysis

The fatty acids profiles of Tunisian Opuntia ficus indica seeds (spiny and thornless form) were investigated. Results of supercritical carbon dioxide (SC-CO2) and soxhlet n-hexane extract were compared. Quantitatively, the better yield was obtained through soxhlet n-hexane: 10.32% (spiny) and 8.91% (thornless) against 3.4% (spiny) and 1.94% (thornless) by SC-CO2 extract (T = 40°C, P = 180 bar, time = 135 mn, CO2 flow rate = 15 mL·s−1). Qualitatively, the main fatty acids components were the same for the two types of extraction. Linoleic acid was the major compound, SC-CO2: 57.60% (spiny), 59.98% (thornless), soxhlet n-hexane: 57.54% (spiny), 60.66% (thornless), followed by oleic acid, SC-CO2: 22.31% (spiny), 22.40% (thornless), soxhlet n-hexane: 25.28% (spiny), 20.58% (thornless) and palmitic acid, SC-CO2: 14.3% (spiny), 12.92% (thornless), soxhlet n-hexane: 11.33% (spiny), 13.08% (thornless). The SC-CO2 profiles fatty acids showed a richness with other minority compounds such as C20:1, C20:2, and C22.The seeds oil was highly unsaturated (US = 4.44–5.25), and the rising temperatures donot affect the selectivity of fatty acids extract by SC-CO2: US = 4.44 (T = 40°C) and 4.13 (T = 70°C).

Phenolic Contents and Antioxidant Potential of Crataegus Fruits Grown in Tunisia as Determined by DPPH, FRAP, and β-Carotene/Linoleic Acid Assay

Crataegus fruit is one of most important fruits in Tunisian flora. Some fruits of this genus are edible. This study was undertaken in order to examine the benefits of these fruits in human health and their composition of antioxidants including total polyphenol, flavonoids, proanthocyanidins content, and total anthocyanins. The antioxidative properties of the ultrasonic methanolic extract were assessed by different in vitro methods such as the FRAP, DPPH, and β-carotene/linoleic acid assay. We concluded that peel fraction of red fruits possessed relatively high antioxidant activity and might be a rich source of natural antioxidants in comparison with the pulp and seed fruit extract. The results also showed that hawthorn yellow fruit presents lower amounts of phenolic content, absence of anthocyanins, and less antioxidant capacity. Most of peel and seed fractions were stronger than the pulp fractions in antioxidant activity based on their DPPH IC50, FRAP values, and results of β-carotene/linoleic acid. The total phenolic compounds contents were also highly correlated with the DPPH method and the FRAP assay.

Removal of ibuprofen, naproxen and carbamazepine in aqueous solution onto natural clay: equilibrium, kinetics, and thermodynamic study

This study aimed to describe the adsorption of three pharmaceuticals compounds (ibuprofen, naproxen and carbamazepine) onto natural clay on the basis of equilibrium parameters such as a function of time, effect of pH, varying of the concentration and the temperature. Adsorption kinetic data were modeled using the Lagergren’s first-order and the pseudo-second-order kinetic equations. The kinetic results of adsorption are described better using the pseudo-second order model. The isotherm results were tested in the Langmuir, Freundlich and Dubinin–Radushkevich models. The thermodynamic parameters obtained indicate that the adsorption of pharmaceuticals on the clay is a spontaneous and endothermic process.

Enolizable Carbonyls and N,O-Acetals: A Rational Approach for Room-Temperature Lewis Superacid-Catalyzed Direct α-Amidoalkylation of Ketones and Aldehydes.

An efficient catalytic room-temperature direct α-amidoalkylation of carbonyl donors, that is, ketones and aldehydes with unbiased N,O-acetals, is described. Sn(NTf2 )4 is an optimal catalyst to promote this challenging transformation at low loading and the reaction shows promising scope. A comprehensive and rational evaluation of this reaction has led to the establishment of an empirical scale of nucleophilic reactivity for a broad set of ketones that should be helpful in the synthetic design and development of carbonyl α-functionalization methods.

Characterization and thermal behavior of HGdP2O7.3H2O

Abstract Crystals of the trihydrated gadolinium diphosphate HGdP 2 O 7 ·3H 2 O were obtained from a mixture of diphosphoric acid and gadolinium nitrate solutions. This salt was characterized by X-ray powder diffraction, IR spectroscopy and thermal analysis. IR spectroscopic study reveals the existence of the characteristic band of the P 2 O 7 group, the ν as (POP) band, at 941 cm −1 and the absence of the ν s (POP) one. The thermal decomposition of HGdP 2 O 7 ·3H 2 O, which was followed by thermogravimetry and differential scanning calorimetry, shows that the elimination of the crystallization water takes place in three stages between 71 and 500°C. The overall ΔH of the first two dehydration were found to be 41.06 and 25.88 kJ/mol. New well-crystallized hydrates HGdP 2 O 7 ·1.5H 2 O and HGdP 2 O 7 ·0.5H 2 O were obtained through heating HGdP 2 O 7 ·3H 2 O, respectively, at 145 and 280°C. The anhydrous HGdP 2 O 7 salt, which was obtained by calcination of HGdP 2 O 7 ·3H 2 O at 530°C, decomposes at 700°C with loss of P 2 O 5 to give the gadolinium diphosphate Gd 4 (P 2 O 7 ) 3 .

Tissue and cellular localization of tannins in Tunisian dates (Phoenix dactylifera L.) by light and transmission electron microscopy.

A histological approach including light microscopy and transmission electron microscopy (TEM) was used to provide accurate information on the localization of condensed tannins in the edible tissues and in the stone of date fruits (Phoenix dactylifera L.). Light microscopy was carried out on fresh tissues after staining by 4-dimethylaminocinnamaldehyde (DMACA) for a specific detection of condensed tannins. Thus, whether under light microscopy or transmission electron microscopy (TEM), results showed that tannins are not located in the epidermis but more deeply in the mesocarp in the vacuole of very large cells. Regarding the stones, tannins are found in a specific cell layer located at 50 μm from the sclereid cells of the testa.