INHIBITORY EFFECTS OF ANCHUSA AZUREA EXTRACTS ON XANTHINE OXIDASE ACTIVITY AND ITS HYPOURICEMIC EFFECTS ON MICE

Objective: The aim of the present study was to determine the effects of the polyphenols and flavonoids from Anchusa azurea on XO activities in vitro and on serum and liver uric acid levels in normal and potassium oxonate-induced hyper uricemic mice. In addition, the renal function of the mice after flavonoid administration was estimated by the determination of blood urea and creatinine analysis.Methods: In the present study, Anchusa azurea were extracted with solvent of varying polarity allowed its separation into four subfractions: crude extract (Cr) chloroform extract (ChE), ethyl acetate extract (AcE), and aqueous extracts (AqE). Total polyphenol and flavonoids contents of Anchusa azurea extracts were determined. The inhibitory activity of the extracts on the XO was evaluated and the type of inhibition was determined. Hyperuricemia is induced by intraperitoneally injection of potassium oxonate, the uric acid, urea and creatinine were measured in serum and supernatant of the liver. The effect of the extracts on renal function was evaluated. The rate of urea and creatinine levels can be indicators for the assessment of renal function.Results: AcE were the richest in polyphenols and ChE was the richest fraction in flavonoids. The inhibitory activity of the extracts on the XO was evaluated, the results obtained showed that the inhibition is dose-dependent and ChE and AcE have the best inhibitory effect (IC50= 0.334±0.006 and 0.263±0.002 mg/ml, respectively), and both showed a noncompetitive type of inhibition. For antihyperuricemic effect, AqE and CrE caused a decrease in serum uric acid (a decrease of 66%) followed by ChE with a percentage of 29.22 %. The AcE keeps almost the same value of uric acid of "PO" group. For the supernatant, only CrE caused a significant decrease of liver uric acid (18.5±4.83 mg/l). This decrease can be explained by the significant inhibition of the XO by inhibition of the synthesis pathways of uric acid. Comparing the urea level of "OP" group (0.48 g/l), only extracts CrE-AA, AqE-AA (0.41g/l, 0.39 g/l) decreased the level of urea significantly (P ≤ 0.05) to the normal values of urea (0.34 g/l), we can conclude that the rate of urea and creatinine after treatment with plant extracts are normal and that the results of this study indicate the absence of renal damage in miceConclusion: Anchusa azurea fractions have a strong inhibitory effect on xanthine oxidase and also have a significant lowering effect on serum and liver creatinine and urea levels in hyper uricemic mice.Â

Effet de quelques flavonoïdes sur une pénicillinase de Bacillus cereus

L’effet inhibiteur de certains flavonoïdes sur l’activité d’une β-lactamase d’une souche de Bacillus cereus a été testé et la relation structure-fonction a été établie. L’activité de La β-lactamase est déterminée en présence de différentes concentrations de la pénicilline G; le Km est de 106,3256 ± 32,0861 µM et la Vmax est de 0,6836 ± 0.00974 µM/min. Ces résultats reflètent une affinité de l’enzyme sur la pénicilline G. Six molécules de flavonoïdes ont été testées pour leur capacité à inhiber la b-lactamase. Le type d’inhibition et les constantes d’inhibition (Ki) ont été déterminés à une concentration de 150 µM. Parmi les molécules testées, l’épicatéchine et la naringine sont des inhibiteurs incompétitifs. La catéchine, la morine et la rutine sont des inhibiteurs compétitifs. La naringénine ne présente aucun effet inhibiteur. Les flavonoïdes ont une fonction 4-oxo semblable à celle de l’acide clavulanique et la pénicilline G. Il semble que le type du cycle, la position de OH et la présence d’un sucre dans les structures des molécules ont une importance majeure

Effect of thermal treatment on the mechanical and viscoelastic response of polypropylenes incorporating a β nucleating agent

The influence of two thermal treatments on the structure, morphology, and ultimate properties exhibited by isotactic polypropylene (iPP), synthesized by conventional Ziegler–Natta iPP (Z-iPP) or metallocene iPP (m-iPP) catalysts, has been investigated in the present work. Novelty of this research consisted in the incorporation of a β nucleating agent in two different contents to the m-iPP. Results attained are compared with those found in the Z-iPP and important differences are observed. Differential scanning calorimetry and X-ray diffraction experiments revealed that coexistence of different crystalline lattices took place depending on the type of iPP: β and α forms were found in the β nucleated Z-iPP specimens, whereas α, β, and γ polymorphs could be developed in the m-iPP with nucleating agent. On the other hand, the iPP glass transition temperature (T) did not exhibit a significant change because of the addition of β nucleant, as deduced from Dynamic Mechanical Thermal Analysis (DMTA) analysis. Moreover, the size and shape of the iPP spherulites was totally changed by the presence of the β agent. This nucleant promoted the formation of smaller spherulites in a greater amount, as demonstrated by optical microscopy. Concerning the mechanical parameters, microhardness, MH, and Young modulus, E, values were in the fast crystallized samples lower than those presented by their slowly cooled counterparts. A good balance in properties was seen for the slowly crystallized m-iPP that incorporated a 5 wt% content in β nucleating agent, this fact being ascribed to the coexistence of the three α, β, and γ polymorphs

Composites of a polypropylene random copolymer and date stone flour: Crystalline details and mechanical response

Several composites were prepared based on a polypropylene random copolymer (PPR) and different amounts of date stone flour (DSF). This cellulosic fiber was silanized beforehand in order to reduce its hydrophilicity and improve the interfacial adhesion with the polymer. Other composites were also obtained, including a sorbitol derivative as an effective nucleant. Films made from these composites were prepared using two different thermal treatments, involving slow crystallization and rapid cooling from the melt. Scanning electron microscopy was used to evaluate the morphological features and the DSF particle dispersion within the PPR matrix. X‐ray diffraction experiments and differential scanning calorimetry tests were employed to assess the crystalline characteristics and for the phase transitions, paying especial attention to the effects of the DSF and nucleating agent on PPR crystallization. An important nucleation ability was found for DSF, and evidently for the sorbitol derivative. The peak crystallization temperature upon cooling was considerably increased by the incorporation of either the nucleant or DSF. Additionally, a much higher proportion of orthorhombic crystals developed in relation to the monoclinic ones. Moreover, the mechanical responses were estimated from the microhardness experiments and significant improvements were found with increasing DSF contents. All of these findings indicate that the use of silanized DSF is a fairly good approach for the preparation of polymeric eco‐composites, taking advantage of the widespread availability of this lignocellulosic material, which is otherwise wasted.This research was funded by AEI/FEDER, UE (grant number MAT2016-79869-C2-1-P), and CSIC (grant number 2020AEP129

Kinetics of Inhibition of Xanthine Oxidase by Lycium arabicum and its Protective Effect against Oxonate- Induced Hyperuricemia and Renal Dysfunction in Mice

Purpose: To evaluate the in-vitro inhibition of xanthine oxidase (purified from bovine milk) by extracts of Lycium arabicum, as well as it is in vivo hypouricemic and renal protective effects.Methods: Four extracts of Lycium arabicum, methanol (CrE), chloroform (ChE), ethyl acetate (EaE) and aqueous (AqE) extracts, were screened for their total phenolics and potential inhibitory effects on purified bovine milk xanthine oxidase (XO) activity by measuring the formation of uric acid or superoxide radical. The mode of inhibition was investigated and compared with the standard drugs, allopurinol, quercitin and catechin. To evaluate their hypouricemic effect, the extracts were administered to potassium oxonate-induced hyperuricemic mice at a dose of 50 mg/kg body weight.Results: The results showed that EaE had the highest content of phenolic compounds and was the most potent inhibitor of uric acid formation (IC50 = 0.017 ± 0.001 mg/mL) and formation of superoxide (IC50 = 0.035 ± 0.001 mg/ml). Lineweaver-Burk analysis showed that CrE and EaE inhibited XO competitively, whereas the inhibitory activities exerted by ChE and AqE were of a mixed type. Intraperetoneal injection of L. arabicum extracts (50 mg/kg) elicited hypouricemic actions in hyperuricemic mice. Hyperuricemic mice presented a serum uric acid concentration of 4.71 ± 0.29 mg/L but this was reduced to 1.78 ± 0.11 mg/L by EaE, which was the most potent hyporuricemic extract.Conclusion: L. arabicum fractions have a strong inhibitory effect on xanthine oxidase and and also have a significantly lowering effect on serum and liver creatinine and urea levels in hyperuricemic mice.Keywords: Lycium arabicum, Uric acid, Creatinine, Superoxide, Phenolic compounds, Flavonoids, Hyperuricemi

Prediction study of structural, electronic and optical properties of 4C16H10Br2O2 Bis (m-bromobenzoyl) methane crystals

By first-principles calculations with density functional theory and a pseudopotential approach, the structural, electronic, and optical properties of the anhydrous 4C16H10Br2O2 Bis (2-Bromobenzoyl) Methane crystals in Pbnc (N°60) and P21/c (N°14) space group are investigated. All computations are determined by a generalized gradient approximation, local density approximation and an ultra-soft pseudopotential. The calculated equilibrium parameters are in good agreement with their available experimental data. This calculation shows that the GGA/PW91 functional overestimate the lattice constant, unlike the LDA/CA-PZ. The Br–C bond distance of 1.856 (1.902) Å is comparable with experimental value of 1.901 (1.896) Å in Pbnc (P21/c) space groups. The direct band gap nature is obtained for both space groups Pbnc and P21/c, since the maximum of the valence band and the minimum of the conduction band are both situated at the YA center

On a contribution to study some mechanical properties of WEEE recycled polymer blends

This research deals with the study of acrylonitrile-butadiene-styrene/polycarbonate (ABS/PC) totally derived from wastes of electrical and electronic equipment (WEEE). The aim of this study is to investigate the macroscopic use properties of 100% recycled polymers and compare them with the virgin materials. First, a preliminary work of sorting and characterization of the wastes was necessary to identify the predominant polymer components in the lots. Then, four compositions of blends (ABS/PC) were performed at laboratory using the twin-screw extruder and injection techniques. Next, a series of experimental tests were carried out to investigate the morphology of the blends, their mechanical and thermo-mechanical behavior. The experimental results highlighted the synergistic effect by blending ABS and PC wastes. In addition, the comparison with the virgin mixtures has shown a decrease in the mechanical properties of the waste blends, however, the mechanical behavior is still ductile and the blends stiffness was enhanced