Chemical composition and antioxidant activity of Borago officinalis L. leaf extract growing in Algeria

The aqueous and hydroalcoholic extracts of borage (Borago officinalis) leaves from Annaba region (Algeria) were preliminary analyzed for their phenolic profile (total phenolics, total flavonoids, total flavonols, total tannins and total anthocyanins). These extracts were evaluated for their antioxidant properties by different methods such as DPPH radical scavenging, test NBT and total antioxidant activity. The two extracts have exhibited a high antiradical capacity. Indeed, the ethanolic extract showed the lower IC50 values and the highest amount of phenolics (94.09 ± 1.72 mg gallic acid/g dry extract). Using LC-MS/MS analysis, it was possible to identify phenolic acids, flavonoids, sterol and for the first time oleuropein was identified in the aqueous extract of the plant. The obtained results have demonstrated that phenolic compounds are the major contributor to the antioxidant activity of plants.     

A new class of heterocycles: 1,4,3,5-oxathiadiazepane 4,4-dioxides

This work reports the synthesis of novel 1,4,3,5-oxathiadiazepanes 4,4-dioxides from the reaction of N'-benzyl-N-(2-hydroxyethyl)-sarcosine or proline sulfamide with aromatic aldehydes under acid catalysis. To prepare the starting materials N-Boc-sulfamide derivatives of sarcosine or proline were alkylated with benzyl alcohol under Mitsunobu reaction conditions, the Boc group was removed chemoselectively by acidolysis, and the resulting product reduced to the corresponding alcohol in good yields.     

Isochronous and Strongly Isochronous Foci of Polynomial Liénard Systems

Differential Equations - The real Liénard system $$\dot x=-y$$ , $$\dot y=x+A(x)-B(x)y$$ , where the polynomials $$A(x) $$ and $$B(x) $$ and the derivative $$A^{\prime }(x) $$ satisfy the...     

Chemical constituents,in vitro antioxidant and antimicrobial properties of ethyl acetate extract obtained from Cytisus triflorus l’Her

Abstract

The present study investigates the phenolic composition, antioxidant and antimicrobial activities of an ethyl acetate extract from C. triflorus L’Her. The phytochemical study on the aerial parts of C. triflorus belonging to the Fabaceae family led to the isolation and structural elucidation of 5-Hydroxy-7-O-glucosylflavone (P1), 5-Hydroxy-7-O-galactosylflavone (P2), 5,7-Dihydroxy-flavone (P3), 5,7,3’-Trihydroxy,4’-methoxy-flavone (P4). These compounds were identified by 1D and 2D NMR combined analysis as well as by UV.

Ethyl acetate extract of C. triflorus showed a significant and dose-dependent antioxidant activity in vitro, related to the presence of phenolics (180.33?±?12.22?µg GAE/mg) and flavonoids (16.78?± 1.54?µg QE/mg). The antimicrobial activity was evaluated in vitro against Staphylococcus aureus CECT 240 and Escherichia coli CECT 4099, by agar-diffusion method. The most active antibacterial activity was expressed by ethyl acetate extract of C. triflorus against Gram-positive bacteria S. aureus. The gathered results suggest that C. triflorus polyphenols and flavonoids are closely associated to its antioxidant and antimicrobial properties.     

Functionalization of Pasteurized Milk Using Rosemary,Thyme, and Ammoides Aqueous Extracts for Better Microbial Quality and an Improved Antioxidant Activity

This study aimed to evaluate the effects of thyme (Thymus vulgaris L.), rosemary (Rosmarinus officinalis L.), and ammoides (Ammoidespusilla L.) aqueous extracts supplementation on the quality of heat-treated (55, 65, and 75 °C) raw milk (sample lots: A, B, and C) and cold-stored pasteurized milk (lot D). The three herbs have shown rich polyphenol contents (32.65–104.23 mgGAE/g), relevant antioxidant capacity, and high caffeic and rosmarinic acids and catechin contents. A significant reduction in psychrotrophic and total viable bacteria counts (PC and TVC) was attained following milk extract supplementation in both experiments. Monitoring PC and TVC counts in sample lots (A, B, and C) has revealed a significant improvement in extracts’ effectiveness in reducing the TVC count with the increment of temperature. The highest reductions of PC and TVC counts were achieved, respectively, in samples treated with thyme and rosemary in (lots: A, B, and C) and in samples treated with ammoides and thyme in (lot D). Thyme extract showed the highest milk serum DPPH scavenging activity (74.84% at 0.1 mg/mL) and induced a significant Listeria monocytogenes growth inhibition (>1 Log cycle). The sensory evaluation of supplemented milk has shown good consumer acceptability of ammoides-supplemented milk, quite similar to the control sample.     

Synthesis of New Spirocyclopropane and Oxadiazole Products

In explorations of synthesis and chemistry of spiroheterocycles, we found that the reaction of 2‐diazopropane with arylidene‐benzofuran‐2(3H)‐one and arylidene‐benzofuran‐3(2H)‐one derivatives generated the spirocyclopropane products. In addition to the expected cycloadducts, an unexpected oxadiazole was formed in some cases. The structures of the obtained adducts have been assigned by means of spectroscopic methods.     

Synthesis,characterization and optical properties of ZnO nanoparticles with controlled size and morphology

Zinc oxide monodispersed nanoparticles were synthesized using a modified polyol process without any requirement to use a catalyst or calcination step at high temperature. The morphology and the size of the resulting oxide particles were adjusted by using several synthesis parameters (temperature, alkaline ratio, hydrolysis ratio, etc.). The increasing of the alkaline ratio results in a great change of the elaborated particles morphology that evolved from irregular and anisotropic forms (conical, nanorod-like and elliptical) to spherical one. A growth mechanism of these particles was proposed on the basis of zincite crystal structure and the morphology evolution as a function of the synthesis parameters. The photoluminescence spectra show UV-excitonic and visible emission bands. The strongest intensity of the visible emission was observed in nanorod-like particles, which implies an increased fraction of oxygen vacancies in this sample. The rod-like particles with 1 μm length show the dominant UV-emission, which evidences their improved stoichiometry.     

Construction of a Pfaff system of Fuchs type with three singular surfaces on a complex projective space

We construct a multidimensional Pfaff equation of Fuchs type for a given monodromy group on CP ⁿ . The monodromy group is generated by three noncommutating matrices.