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Diabetes mellitus is a major risk factor for cardiovascular complications. The present study was designed to investigate the possible hypoglycaemic, hypolipidaemic and antioxidant effects of a lyophilised methanolic extract of Globularia alypum L. (Ga). Twenty rats with diabetes were divided into two groups that were fed a casein diet either with or without a Ga supplement for 28 d. Diabetes was induced in the rats by administration of a single dose of streptozotocin (50 mg/kg; intraperitoneally). Plasma total cholesterol (TC), TAG, VLDL-LDL-TC and HDL-TC and the content of final lipid peroxidation products reacting with thiobarbituric acid (TBARS) in several tissues, as well as the concentration of reduced glutathione (GSH) and antioxidant enzyme activities were evaluated. A significant reduction in plasma glucose was observed in rats treated with Ga (5.21 (SE 0.83) mmol/l) compared with untreated rats (27.4 (SE 0.21) mmol/l). TC, VLDL-LDL-TC and TAG were respectively 1.3-, 1.8- and 1.6-fold higher for Ga-treated rats than for untreated rats, whereas there was no significant difference in HDL-TC. Compared with the untreated group TBARS were diminished by 43, 51, 42 and 23% in liver, heart, brain and kidney respectively in the Ga-treated group, although in adipose tissue and gastrocnemus muscle the concentrations were similar for both groups. GSH levels were increased by 40, 25 and 36% in liver, brain and kidney respectively, whereas values in heart and muscle were similar. In liver and kidney superoxide dismutase (SOD), GSH peroxidase (GSH-Px), glutathione reductase and catalase (CAT) activities were increased significantly in Ga-treated rats compared with untreated rats (P<0.05). Moreover, for Ga-treated rats SOD activity was increased by 22% in muscle, while GSH-Px and CAT activities were 1.3- and 1.4-fold higher in heart compared with untreated rats. Administration of Ga to rats with diabetes leads to lower glycaemia and plasma lipids. Moreover, this plant exerts a beneficial action against tissue lipid peroxidation by enhancing antioxidant enzyme activities.

 
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Portulaca oleracea (Po) has been used as one of the traditional edible and medicinal plant in Algeria to treat diabetes and enhancing immunity. The aim of the present study was to investigate the possible antihyperglycemiant and hypolipemiant effects of Po lyophilized aqueous extract, in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in male Wistar rats (n=12), weighing 263±5g, by a single intraperitoneal injection of STZ (60mg/kg body weight). Diabetic rats were divided into two groups. The untreated group received a 20% casein diet (D) and the treated group received the same diet supplemented with Po lyophilized aqueous extract (1 g/100 g diet) (DPo), for 4 weeks. According to thin layer chromatography assay, the main chemical groups detected are flavonoids, alkaloids, and terpenoids. During all the experiment in spite of similar food intake in the 2 groups, there was a significant decrease in the body weight. At d28, in Po treated vs untreated diabetic group, glycemia and glycosylated haemoglobin (HbA1c) were reduced by 61% and 41%, respectively, whereas insulinemia was similar. Plasma cholesteryl esters (CE), triacylglycerols (TG) and phospholipids (PL) concentrations were decreased by 48%, 53% and 62%, respectively. The hypolipidemic effect induced by Po extract was due to the reduction of total cholesterol (TC) in VLDL (-28%), LDL-HDL1 (-51%) and C-HDL3 (-21%), and a decrease of TG in VLDL (-71%), LDL-HDL1 (-68%) and HDL2 (-30%). Quantitatively, VLDL, LDL-HDL1, HDL2 and HDL3 lipoproteins mass was respectively 2.9-, 4.1-, 1.5- and 2.5-fold lower and concomitant with the reduced levels of unesterified cholesterol (UC) (-55%), CE (-17%) and -PL (-72%) in VLDL fraction, and UC (-36%), -CE (-56%) and PL (-82%), in LDL-HDL1. Po treatment improved lecithin:cholesterol acyltransferase (LCAT) activity by 48% and its cofactor-activator, the plasma apolipoprotein (apo) A-I by 52%.. HDL3-UC (acyl group acceptor) and -PL (enzyme substrate) were diminished respectively by 47% and 82%, whereas HDL2-CE concentrations (product of LCAT reaction) were increased by 44%. In STZ-induced diabetic rat, Portulaca oleracea lyophilized aqueous extract possesses antihyperglycemiant and hypolipemiant effect by improving lipoprotein profiles. Po extract may be useful in the prevention and treatment of diabetes and dylipidemia.

 
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The effects of Portulaca oleracea (Po) lyophilized aqueous extract were determined on the serum high-density lipoproteins (HDL2 and HDL3) amounts and composition, as well as on lecithin: cholesterol acyltansferase (LCAT) activity. Methods Male Wistar rats (n = 12) were fed on 1% cholesterol-enriched diet for 10 days. After this phase, hypercholesterolemic rats (HC) were divided into two groups fed the same diet supplemented or not with Portulaca oleracea (Po-HC) (0.5%) for four weeks. Results Serum total cholesterol (TC) and triacylglycerols (TG), and liver TG values were respectively 1.6-, 1.8-, and 1.6-fold lower in Po-HC than in HC group. Cholesterol concentrations in LDL-HDL1, HDL2, and HDL3 were respectively 1.8, 1.4-, and 2.4-fold decreased in Po-HC group. HDL2 and HDL3 amounts, which were the sum of apolipoproteins (apos), TG, cholesteryl esters (CE), unesterified cholesterol (UC), and phospholipids (PL) contents, were respectively 4.5-fold higher and 1.2-fold lower with Po treatment. Indeed, enhanced LCAT activity (1.2-fold), its cofactor-activator apo A-I (2-fold) and its reaction product HDL2-CE (2.1-fold) were observed, whereas HDL3-PL (enzyme substrate) and HDL3-UC (acyl group acceptor) were 1.2- and 2.4-fold lower. Conclusion Portulaca oleracea reduces triglyceridemia, cholesterolemia, and improves reverse cholesterol transport in rat fed enriched-cholesterol diet, contributing to anti-atherogenic effects.

 
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The beneficial health effects of plant polyphenols were frequently attributed to their powerful hypolipemiant and antioxidant effects. We hypothesized that administration of Globularia alypum (Ga) lyophilized methanolic extract would ameliorate glycemia, lipid parameters, reverse cholesterol transport, as well as lipoproteins peroxidation, in diabetic rats. Diabetes was induced in male Wistar rats, weighing 250±10 g by a single intraperitoneal injection of streptozotocin (STZ) (55 mg/kg body weight). Diabetic rats (n=20) were divided into two groups, and fed during 4 weeks diets containing 20% casein (D) or a casein diet supplemented with a Ga extract (1 g/kg BW) (DGa). At d28, in DGa vs D group, glycemia was lowered by 81%, while insulinemia was markedly increased by 72%. Liver and serum lipid values were significantly decreased (P< 0.05). Lecithin:cholesterol acyltransferase (LCAT) activity was improved (+48%). Indeed, HDL3-PL (enzyme substrate) and HDL3-UC (acyl group acceptor) concentrations were respectively reduced by 50 and 52%, whereas HDL2-CE values (product of LCAT reaction) were increased (+35%). Atherogenicity ratios VLDL-LDL-C/HDL-C, TC/HDL-C and apoB/apoA were lowered respectively by 50%, 25% and 71%. Moreover, VLDL-LDL and HDL3peroxidation was decreased by 47 and 75%, respectively.In STZ-induced diabetic rat, Globularia alypum extract reduces glycemia, liver and serum lipids values, VLDL-LDL and HDL3 lipid peroxidation and ameliorates the reverse cholesterol transport. Therefore, Ga extract may be useful for preventing diabetes and lipid disorders.

[ Modifié: mercredi 15 juillet 2020, 08:59 ]
 
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Aims: In this study, the effects of Portulaca oleracea (Po) in the treatment of hypercholesterolemia combined with diabetes in rats were investigated. Place and Duration of Study: Laboratory of Clinical and Metabolic Nutrition, Department of Biology, Nature and Life Sciences Faculty, University of Oran1, Algeria, between September and July 2017. Study Design: The effects of an aqueous extract from the leaves of Po were studied on glucose homeostasis, lipid parameters, and oxidative stress markers, in streptozotocin (STZ) induced diabetic rats on a cholesterol-enriched diet. Methodology: Experimental hypercholesterolemia was induced by feeding rats with 1% cholesterolenriched diet for 15 days. Hypercholesterolemic male Wistar rats (n=28) were rendered diabetic by a single intraperitoneal injection dose (55 mg/kg BW) of STZ. Hypercholesterolemic diabetic rats were divided into two groups (n=10): Hypercholesterolemic diabetic group (HC-D), and hypercholesterolemic-diabetic group supplemented with 1% of Po aqueous extract (HC-DPo) during 28 days. Assessed parameters were blood glucose, insulinemia, glycosylated haemoglobin (HbA1c), liver and plasma lipids, lipid peroxidation, and antioxidant enzymes in plasma, red blood cells (RBCs), and tissues. Results: A significant increase in final body weight was found between both groups. In HC-DPo vs HC-D group, glycemic parameters were improved by decreasing glucose, HbA1C levels, and by enhancing insulinemia. Low plasma values of total cholesterol (TC) (-42%), triacylglycerols (TG) (-63%), very low and low density lipoprotein cholesterol (VLDL-C, LDL-C) (-66% and -80%), and increase of high density lipoprotein cholesterol (HDL-C) (-26%), leading to decreased atherogenic indices TC/HDL-C (-57%) and LDL-C/HDL-C (-85%) were noted in rats treated by Po compared to untreated group. In the liver, heart and aorta, lipid peroxidation was lowered, and inversely, antioxidant enzymes activities were increased after treatment with Po. Conclusion: On the basis of these finding, it can be concluded that the Po aqueous extract is an interesting natural product to prevent hypercholesterolemia in diabetic rats. Protocols in hypercholesterolemia diabetic patients are needed to verify and validate these results.

 
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Résumé Les plantes médicinales et la phytothérapie sont étroitement liées à l’histoire de l’humanité, elles jouent un rôle important dans la recherche et le développement de nouveaux médicaments, et représentent une branche alternative dans la prévention et le traitement de certaines pathologies. Le pourpier Portulaca oleracea L. (Po), est une plante succulente largement répandue et utilisée à travers le monde pour ses propriétés médicinales et gustatives. Plusieurs travaux menés chez les animaux et l’homme lui attribuent des effets préventifs et curatifs sur plusieurs facteurs de risque cardiovasculaire. Une synthèse bibliographique a été menée sur différents moteurs de recherche scientifique, tels que Pubmed, Scopus, ISI Web of Science et Google Scholar, afin de souligner les travaux de recherche marquant l’effet de Po sur le diabète, l’hyperlipidémie, le stress oxydant et l’inflammation. La présente revue suggère que Po peut avoir des effets bénéfiques significatifs chez le modèle animal ainsi que chez l’homme en améliorant les paramètres glycémiques, lipidiques, antioxydants et antiinflammatoires.

 
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Devant le manque de manuels en cinétique chimique, cet ouvrage didactique est avant tout destiné aux étudiants mais peut également aider les enseignants de cette spécialité à trouver des exercices et des problèmes touchant les différents angles de la cinétique chimique.
Les problèmes et exercices proposés, que nous soumettons à l’attention de l’étudiant sont extraits d’ouvrages divers référencés à la fin, sont aussi le fruit de la réflexion des auteurs.
Loin d’être exhaustifs, les énoncés de ces problèmes et exercices font l’objet de dix (10) chapitres proposés dans le tome I.  
Nous espérons que cette édition rendra des services aux étudiants de graduation de chimie et qu’elle constituera un bon outil de travail et de réflexion dans la résolution de tel ou tel problème.
Les auteurs seront reconnaissants à tout lecteur de l’ouvrage qui voudra bien leur faire part de ses impressions, ses critiques ce qui permettra donc son amélioration.

 

 
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In this paper, which is an extension of a very recent one, we show, in a first part, that starting from RNA, pore exactly, from the detailed atomic composition of its basic components, the four ribonucleotides UMP, CMP, AMP and GMP, full of Fibonacci numbers, we can derive the "One-Number Model" of the genetic code which was introduced by us some years ago, in 2007. In a second and original part, we consider the opposite way, that is, starting from the "One-Number Model", we can recover, in the detail, the atomic composition of the four ribonucleotides, from which we started, and the "circle is complete".

 
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In this short paper, we present an interesting and welcome connection between two different approaches to the mathematical structure of the standard genetic code, we have considered in the last years. The first one relies on the use of the unique number 23! and the second is based on the atomic composition of the four ribonucleotides UMP, CMP, AMP and GMP, the building-blocks of RNA, where several Fibonacci numbers are seen to occur.

[ Modifié: vendredi 29 mai 2020, 22:48 ]