NEPHRO-PROTECTIVE ACTIVITY OF ISOLATED METHANOL FRACTIONS PHYTO-COMPOUND FROM BARK OF TERMINALIA ARJUNA

Objective: The aim of this study was to evaluate the antioxidant property of the isolated phytocompounds from TA (Terminalia arjuna) bark and in vivo study for nephro-protective and oxidative stress reducing activity in experimentally induced albino male rats.Methods: Fractions from methanol crude TA extract were collected by column chromatography and F27, F28, F29 fractions were selected on the basis of antioxidant property by 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay. The in vivo study performed by 30 albino male rats which were randomly divided into five groups: Group I (control)were taken normal food and water, Groups II (uremic) were injected acetaminophen intraperitoneally at the dose of 500 mg/kg/d for 10 d, Group III, IV and V(extract treatment) acetaminophen intraperitoneally at the dose of 500 mg/kg/d for 10 d with co-administered orally of methanol fraction F27, F28, F29 at the dose of 100 mg/kg/d for 15 d respectively.Results: After scarification of rats, the uremic marker plasma urea (80%), creatinine (85%) were elevated and antioxidant enzyme marker such as plasma SOD and catalase level were significantly increased (p<0.05)in Group IV compared to Group II. The total phenolic content of the F28 methanolic fraction was (815.48±8.11) mg gallic acid equivalent/g of extract. For isolation of available compound by 1H NMR study in F28 methanol fraction of TA bark was arjunoside IV which contained olefinic proton (a pair of carbon atom linked with double bond).Conclusion: Among the three methanolic fraction of TA bark, F28 was shown best antioxidative, nephron-protective and oxidative stress reducing property.Â

Nephroprotective efficacy of Asparagus racemosus root extract on acetaminophen-induced renal injury in rats

Acetaminophen-induced renal necrosis and insufficiency occurs in patients with acetaminophen overdose. Renal failure is rapidly assuming epidemic proportions globally. In absence of reliable and effective nephroprotective drugs, strategies towards exploring alternative therapies for treatment of kidney diseases are essential. Asparagus racemosus is a medicinal plant used for treatment of various ailments. This research was undertaken to investigate the protective effect of ethanol fraction of A. racemosus roots extract in acetaminophen-induced uraemia and renal failure in rats. Rats were co-administered with acetaminophen injection and oral administration of A. racemosus roots extract in an attempt of protection against renal failure. Uremic biomarkers significantly decreased, and elevated levels of antioxidant enzymes were found, in the animals treated with ethanol fraction of A. racemosus when compared with acetaminophen treated uremic animals. Also, histology of kidneys showed control like structure in animals treated with this extract but severe damage in the uremic animals. HPLC analysis of the ethanol fraction of A. racemosus roots extract revealed eight compounds out of which one had a retention time near to the quercetin standard. It may be concluded that this extract of A. racemosus has therapeutically useful nephroprotective potential

Étude de catalyseurs à trois voies à base de pérovskite par analyses de surface et par spectroscopie in situ/operando

Le post-traitement catalytique des gaz d’échappement des moteurs à essence nécessite la conversion simultanée de CO,NO et des hydrocarbures. Ce procédé est connu sous le nom de catalyse trois voies (TWC). Les matériaux à base de perovskites comme LaFeO3, décrits comme des supports "intelligents", sont considérés comme des candidats potentiels dans la recherche d’alternatives aux catalyseurs trois voies classiques, dans un contexte de réduction de leur teneur en métaux nobles. Ces catalyseurs massiques présentent en surface une composition souvent différente de leur formule chimique, qui caractérise ces matériaux dans leur volume. Etant donné que, en catalyse hétérogène, la surface est déterminante pour les performances catalytiques, il est impératif de mieux comprendre les caractéristiques de la surface, en particulier dans des conditions aux plus proches de celles de la réaction. Ainsi, des catalyseurs modèles plans à base de LaFeO3,imitant les catalyseurs conventionnels sous forme de poudre, ont été étudiés en combinant des techniques avancées d’analyses de surface comme XPS, LEIS et ToF-SIMS pour étudier les variations de surface à différentes échelles de profondeur. De plus, le comportement des catalyseurs a été étudié sous atmosphère CO par NAP-XPS et GI-XANES. Cette méthodologie a permis de révéler qu’une composition déficitaire en La induit dans la structure permet d’améliorer les performances catalytiques grâce à un effet d’interface entre la perovskite et une phase minoritaire d’oxyde de fer. En outre, les différents modes de fonctionnement catalytiques de poudre de pérovskites substituées au Cu ou Mn ont été déterminés par spectroscopie Raman in situ et operando.The catalytic after-treatment of exhaust gases from gasoline engines requires simultaneous abatement of CO, NO and hydrocarbons and is commonly called three-way catalysis (TWC). Perovskites based materials like LaFeO3, regarded as intelligent supports, are being considered as potential candidates as alternative TWC in context of reducing noble metal content. Such bulk catalysts often demonstrate variable surface compositions in comparison to the bulk. Since surface determines the catalytic performance in heterogeneous catalysis, deeper understanding of the surface characteristics especially under relevant reaction conditions becomes imperative. To this end, LaFeO3 based model catalysts relevant to conventional catalysts have been investigated by combination of advanced surface analysis techniques like XPS, LEIS and ToF-SIMS to study the existing surface variations. In addition, catalysts behavior was studied under CO atmosphere by NAP-XPS and GI-XANES. This methodology allowed to reveal that inducing a La-deficiency in the structure helps to improve the catalytic performance due to an interfacial effect. In addition, the different catalytic operating modes of Cu or Mn substituted perovskite powders were determined by in situ/operando Raman spectroscopy

Investigation of perovskite-based model three-way catalysts using surface analysis techniques – XPS/LEIS/ToF-SIMS

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Investigation of perovskite-based model three-way catalysts using surface analysis techniques – XPS / LEIS / ToF-SIMS

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Surface enrichment of Fe species on LaFeO3 model catalysts for CO Oxidation Reaction by Combination of Surface Science Techniques

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Reversible Mobility of Bulk Species in Perovskite Based Three Way Catalysis by Operando/in situ Analyses

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Etude spectroscopique combinée (XPS, LEIS, ToF-SIMS) de catalyseurs trois voies modèles à base de pérovskite

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Therapeutic potential of probiotic Lactobacillus plantarum AD3 on acetaminophen induced uremia in experimental rats

Summary: Background & aims: Chronic kidney disease (CKD) is rapidly heading towards epidemic proportion globally, requires dialysis or kidney transplantation. No generally applicable therapies to slow progression of renal disease are available. The aim of this study was to evaluate Lactobacillus plantarum AD3 as an effective probiotic strain for acetaminophen induced uremic patient. Methods: Plasma uremic profiles, oxidative stress marker, DNA fragmentation assay of kidney tissue and kidney histological studies were investigated on acetaminophen-induced uremic rats (Wister strain albino male). Limited fecal matter analysis and HPLC of intestinal fluid were also performed. Results: In APAP treated rats, plasma urea, creatinine (Cr), glutamate oxaloacetate transaminase (GOT) and malonaldehyde (MDA) level elevated significantly compared to negative control. However, level of plasma urea, creatinine, GOT and MDA in tested rats were significantly lower in comparison to uremic control (p < 0.05). Electrolytes profile of the tested plasma samples were in acceptable range. Glomerular necrosis, DNA damage of uremic rats were also significantly lowered. In contrast, SCFAs have been associated with attenuated kidney damage by protecting against oxidative stress. Conclusion: The urease positive probiotic L. plantarum AD3 strain have the antioxidative and antiuremic efficacy in acetaminophen induced experimental rats. Keywords: Acetaminophen induced uremia, Urease positive probiotic, Lactobacillus plantarum AD3, Rat mode

Evaluating Different Strategies to Minimize cold-start Emissions from Gasoline Engines in steady-state and Transient Regimes

International audienceExhaust car emissions increase significantly at particular gasoline engine driving cycle such as cold-start when the three-way catalyst has not reached its light-off temperature. More efficient technologies are needed to reduce these extra emissions. This study focuses on comparing two strategies to lower cold-start pollutants on a commercial monolithic catalyst: (i) a high content of PGMs (Pd and Rh) loading with a variable concentration distribution along the catalyst, called zone-coating, was investigated in order to take advantages of an in situ pre-heating due to exothermic oxidation processes. And (ii) the use of external device for heating the monolith with the aim to shorten the laps of time to reach the required temperature for their conversion. Both approaches were compared below 300 °C in terms of NO, CO and hydrocarbons conversions as well as N2O formation with respect to homogeneously wash-coated catalyst. For evaluation, complex exhaust gas compositions were considered at different steady-state air-to-fuel λ ratios and high frequency transient lean/rich regime to mimic real operation in gasoline engine exhaust. Results show that a pre-heating of the catalyst at 300 °C is necessary to avoid completely N2O formation from NO reduction with CO. Remarkably higher NO and CH4 conversions were observed during transient regime rather than steady-state lean, rich or stoichiometric conditions at 200 and 300 °C