Biological Properties, Phenolic Profile, and Botanical Aspect of L. and L. Seeds: A Comparative Study.

The use of seeds in the food, pharmaceutical, and cosmetic fields is common, since the iniquity and the virtues of these plants are directly related to their characteristic phytochemical composition. This investigation focused on the comparative study of the botanical aspect, phenolic profile, and in vitro and in vivo biological activities of L. (NS) and L.

Crystal structure, chemical reactivity, kinetic and thermodynamic studies of new ligand derived from 4-hydroxycoumarin: Interaction with SARS-CoV-2.

Currently, Covid-19 pandemic infects staggering number of people around the  and causes a high rate of mortality. In order to fight this disease, a new coumarin derivative ligand (4-[(-3-) ]-2-chromen-2-one) (L) has been synthesized and characterized by single-crystal X-ray diffraction, NMR, ATR, UV-Visible and cyclic voltammetry. Chemical reactivity, kinetic and thermodynamic studies were investigated using DFT method.

Synthesis, spectral characterization, molecular modeling, antibacterial and antioxidant activities and stability study of binuclear Pd(II) and Ru(III) complexes with novel bis-[1-(2-[(2-hydroxynaphthalen-1-yl)methylidene]amino}ethyl)-1-ethyl-3-phenylthiourea] ligand: Application to detection of cholesterol.

A novel bis-[1-(2-[(2-hydroxynaphthalen-1-yl) methylidene]amino}ethyl)-1-ethyl-3-phenylthiourea] Schiff base (L) and its binuclear palladium and ruthenium complexes have been prepared and characterized by ESI-MS, elemental analysis, NMR (H NMR, C NMR, COSY, NEOSY and HSQC), FT-IR, ATR, UV-Visible spectra, TGA measurements, conductivity and cyclic voltammetry. The experimental results and the molecular parameters calculated using DFT method revealed a square planar geometry around Pd and octahedral geometry around ruthenium metal. The antibacterial activity of the ligand L and its complexes was evaluated against different human bacteria.

Electrochemical sensors using modified electrodes based on copper complexes formed with Algerian humic acid modified with ethylenediamine or triethylenetetramine for determination of nitrite in water.

The response and efficiency of new sensors for nitrite ions analysis have been studied electrochemically. These sensors were developed by modifying a carbon paste electrode (CPE) with copper (II) complexes formed with commercial (PFHA) and Algerian (YHA) humic acids and their modified compounds with ethylenediamine (EDA) or triethylenetetramine (TETA). The developed mechanism is based on the electrochemical oxidation of NO2(-) on the modified CPE for different nitrite concentrations.

Use of screen-printed microelectrodes working as generator/collector systems for the determination of the antioxidant capacity of phenolic compounds.

A new method using cheap homemade dual-electrodes has been developed to measure the antioxidant capacity of phenolic compounds. These micro-sized electrodes are elaborated by successive screen-printing of conductive ink and insulator layers and are then used as generator/collector sensors. Cyclic voltammetry and chronoamperometry with a bipotentiostat have been used to test and characterize these sensors.

Evaluation of adsorption capacities of humic acids extracted from Algerian soil on polyaniline for application to remove pollutants such as Cd(II), Zn(II) and Ni(II) and characterization with cavity microelectrode.

The adsorption capacities of new humic acids isolated from Yakouren forest (YHA) and Sahara (Tamenrasset: THA) soils (Algeria) and commercial humic acid (PFHA) on polyaniline emeraldine base (PEB) were studied at pH 6.6. Also the adsorption of heavy metals such as Cd2+, Zn2+ and Ni2+ on humic acid-polyaniline systems (HA-PEB) was investigated at the same conditions.

Radical-scavenging capacity of phenol fractions in the brown seaweed Ascophyllum nodosum: an electrochemical approach.

In this article, the radical-scavenging capacity of phenol fractions extracted from the brown seaweed Ascophyllum nodosum was assessed using in parallel colorimetric methods (ABTS and DPPH) and electrochemistry (cyclic voltammetry). Results obtained by the three methods correlated in the case of global fractions, whereas only ABTS and DPPH correlated when activities were expressed on a phenol basis. The successive fractions separated by both their average molecular size and their polarity exhibited activities largely dependent on their phenol content, suggesting that phlorotannins are the main anti-oxidant molecules in hydro-alcoholic extracts of A.

How do phenolic compounds react toward superoxide ion? A simple electrochemical method for evaluating antioxidant capacity.

The reactivities of different phenols and polyphenols versus superoxide ion (O₂(•-)) were investigated as an easy-to-handle electrochemical method for evaluating antioxidant capacities. In view of this application, the O₂/O₂(•-) couple and associated reactions between O₂(•-) and polyphenols (or phenols) were examined in an aprotic solvent [dimethylformamide (DMF)] by cyclic voltammetry. Comparisons based on simple criteria (reversibility of the O₂ reduction in the presence of the phenolic compound, electron stoichiometry, or apparent kinetic constants) allow discriminations between the possible mechanistic pathways (acid-base or radical reaction type).

Phenolic compounds in the brown seaweed Ascophyllum nodosum: distribution and radical-scavenging activities.

Introduction: Phenolic compounds are metabolites exhibited at high levels in Phaeophyceae. Although several studies have been conducted on total phenol contents, no one to our knowledge has dealt with the contents of phenolic compounds and antioxidant activities on purified fractions.

Objective: The purpose of this study was the extraction and purification of phenolic compounds from the brown seaweed Ascophylllum nodosum, to determine both their distribution and their radical-scavenging activities, and to obtain a sufficiently purified oligophenolic fraction to perform an RP-HPLC analysis on molecules with a molecular weight (MW) < 2 kDa.

Superoxide protonation by weak acids in imidazolium based ionic liquids.

The reactivity of the superoxide anion versus a series of substituted phenols was investigated in a common ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIm][TFSI]) and for comparison in dimethylformamide (+0.1 mol x L(-1) of Bu4NPF6 as supporting electrolyte). On the whole, the mechanism of the reduction of O2 in the presence of the different phenols was found to be very similar in [BMIm][TFSI] and in DMF: A 2-electron mechanism involving a succession of electrochemical and protonation steps.

A DFT and experimental investigation of the electron affinity of the triscyclopentadienyl uranium complexes Cp3UX.

Relativistic Density Functional Theory (DFT) based methods coupled with the Conductor-like Screening Model (COSMO) for a realistic solvation approach are used to investigate the electron affinity (EA) of a series of triscyclopentadienyl uranium complexes Cp(3)UX (X = Cl, BH(4), SPh, S(i)Pr and O(i)Pr) related to the U(iv)/U(iii) redox system. E(1/2) half-wave potentials have been measured in solution (THF) under the same rigorous conditions for all the species under consideration. A good correlation (r(2) = 0.

Validation of a new method using the reactivity of electrogenerated superoxide radical in the antioxidant capacity determination of flavonoids.

This article lays out a new method to measure the antioxidant capacity of some flavonoids. The methodology developed is based on the kinetics of the reaction of the antioxidant substrate with the superoxide radical (O(2)(*-)). A cyclic voltammetric technique was used to generate O(2)(*-) by reduction of molecular oxygen in aprotic media.