SYNTHESIS AND EVALUATION OF ANTIMICROBIAL PROPERTIES OF AZO DYES

Objective: To synthesise and evaluate the antimicrobial potential of azo dyes in the quest of discovering lead molecules.Methods: A number of azo compounds have been synthesized via diazotization of the primary aromatic amine and subsequent coupling with naphthols or other coupling partners. The antimicrobial properties of these azo compounds were determined against six microbes; Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC10231), Mycobacterium smegmatis (clinical strain), Micrococcus luteus (ATCC10240), Pseudomonas aureginosa (ATCC 9027) and the fungi species Candida albicans (ATCC10231) using the Kirby-Bauer Standard disc diffusion method. The minimum inhibition concentrations were also determined for those that exhibited antimicrobial activity.Results: Two of the azo compounds showed antimicrobial potential with p-NAαN in particular exhibiting very good antimicrobial properties. However, Pseudomonas aureginosa (ATCC 9027) was resistant to all the azo compounds.Conclusion: During effective in-vitro control,p-NAαN showed broad spectrum of activity against Staphylococcus aureus, Escherichia coli, Mycobacterium smegmatis, Micrococcus luteu sand the fungi species Candida albicans, with p-ABAα Nexhibiting activity against Candida albicans

A pivotal role for interleuking-4 in Atorvastatin-associated neuroprotection in rat brain.

noInflammatory changes, characterized by an increase in pro-inflammatory cytokine production and up-regulation of the corresponding signaling pathways, have been described in the brains of aged rats and rats treated with the potent immune modulatory molecule lipopolysaccharide (LPS). These changes have been coupled with a deficit in long-term potentiation (LTP) in hippocampus. The evidence suggests that anti-inflammatory agents, which attenuate the LPS-induced and age-associated increase in hippocampal interleukin-1ß (IL-1ß) concentration, lead to restoration of LTP. Here we report that atorvastatin, a member of the family of agents that act as inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase, exerts powerful anti-inflammatory effects in brain and that these effects are mediated by IL-4 and independent of its cholesterol-lowering actions. Treatment of rats with atorvastatin increased IL-4 concentration in hippocampal tissue prepared from LPS-treated and aged rats and abrogated the age-related and LPS-induced increases in pro-inflammatory cytokines, interferon-¿ (IFN¿) and IL-1ß, and the accompanying deficit in LTP. The effect of atorvastatin on the LPS-induced increases in IFN¿ and IL-1ß was absent in tissue prepared from IL-4¿/¿ mice. The increase in IL-1ß in LPS-treated and aged rats is associated with increased microglial activation, assessed by analysis of major histocompatibility complex II expression, and the evidence suggests that IFN¿ may trigger this activation. We propose that the primary effect of atorvastatin is to increase IL-4, which antagonizes the effects of IFN¿, the associated increase in microglial activation, and the subsequent cascade of events

Nuclear magnetic resonance and chromatographic studies of host and parasite lipids

One-dimensional and 2-dimensional proton nmr techniques were used to characterise and quantify lipids extracted from host (blood) and parasites including Leishmania donovani, L. major, L. mexicana, L. infantum, Giardia lamhlia. Entamoeba histolytica and the non- parasitic protozoan, Tetrahymena thermophila. Phospholipid classes and subclasses, sterols, triglycerides, metabolic changes in lipids as well as fatty acid composition of glycerophospholipids were determined from structure-specific proton resonances and confirmed by cross peaks in the 2-D COSY spectra of lipid extracts. Phosphatidylcholine, ethanolamine phospholipids and sphingomyelin were the principal phospholipids found in the erythrocyte membrane. Cholesterol, the only neutral lipid, was present in roughly equal proportion to the total phospholipids. Ethanolamine lipids were present in diacyl and alkenylacyl forms. Phosphatidylcholine was the major phospholipid in the plasma and was quantified together with cholesterol, cholesterol esters, triglycerides and lysophospholipids. Leishmania lipid composition differed substantially from the hosts. The major phospholipids determined were those of choline, ethanolamine and inositol. The choline lipids were mainly diacyl, the ethanolamine lipids were predominantly plasmenyl while the inositol lipids existed in diacyl, alkylacyl and ceramide forms. Several sterols were detected from nmr spectra where parasite-specific ergosterol-type sterols exceeded cholesterol. The glycerophospholipids of Giardia (phosphatidylglycerol as major lipid) and Entamoeba (phosphatidylcholine as major lipid), unlike blood and Leishmania, carried predominantly saturated and monounsaturated fatty acids and were present in the diacyl form. From Tetrahymena, the determination of phosphonolipids in addition to normal phospholipids was achieved; its lipid extract contained a high proportions of alkylacyl forms. The successful analysis of 1-acyl and 2-acyl-lysophospholipids from plasma, Leishmania and Entamoeba makes the application of proton nmr to the study of phospholipases A desirable. These analyses agreed substantially with other published information and therefore, makes proton nmr potentially useful in future parasite lipid research

Développement de méthodes LC-MS pour l'identification des triglycérides dans les huiles de graines de résineux

Cette thèse a consisté à développer une nouvelle stratégie analytique en utilisant le couplage chromatographie liquide - spectrométrie de masse (LC-MSn) afin d identifier dans les huiles et corps gras, les triglycérides (TAGs) et leur régio-spécificité. Cette méthodologie analytique générale a été appliquée à 8 huiles de graine de résineux en particulier, à l huile de pignon de Pinus Koraiensis car ses TAGs sont constitués d acides gras, possédant une double liaison en position 5, non-méthylène alternée, susceptibles de jouer un rôle anti-cholestérol chez l homme.La thèse se décompose en quatre chapitres: les deux premiers, bibliographiques, traitent respectivement de la taxonomie des 8 résineux étudiés, de la composition en acide gras (AG) de leur graine et des techniques analytiques déjà décrites pour caractériser les TAGs. Le troisième chapitre, expérimental, est dédié au développement de nouvelles stratégies analytiques NARP-LC-MSn mises en place pour identifier les TAGs présents dans les huiles et plus particulièrement à l huile de pignon de Pinus Koraiensis. Grâce à l ajout post colonne de sel d argent, il a été possible de déterminer de manière non ambigüe la structure de tous les TAGs d un lipide, même ceux présents en faible quantité, par Ag+-NARP-LC-MS mais aussi de déterminer la structure de chaque AG constitutif d un TAG par fragmentation de l adduit moléculaire par Ag+-NARP-LC-MS2. Le problème de la distinction des TAGs ayant la même masse moléculaire, les mêmes longueurs de chaine mais des positions de double liaisons différentes, a été résolu en développant une méthode d identification des TAGs à partir des lois de rétention chromatographiques qui relient linéairement le logarithme du facteur de rétention de chaque TAG soit au nombre total de carbone soit au nombre total de double liaisons. Cette étude a permis d identifier 22 nouveaux TAGs parmi un nombre total de 58 TAGs caractérisés. Elle a amené la preuve que le résidu AG saturé à 17 atomes de carbone est ramifié et non linéaire. Elle a mis en évidence la présence de trois AGs constitutifs qui n ont jamais été décrit: 19:1, 19:2 et 24:0 dans l huile de pignon de Pinus Koraiensis. Le quatrième chapitre porte sur le développement de trois méthodes de détermination de la régiospécificité des TAGs, grâce à la seule SM: (1) une méthode Ag+-NARP-LC-ESI-MS2 utilisant les rapports des ions diglycériques des TAGs. Il en ressort que cette méthode n est pas assez fiable pour déterminer la structure des TAGs. (2) la seconde méthode fait appel à des expériences MS4/ MS5 sur les adduits argent des TAGs. Elle s avère pertinente à condition d avoir à disposition les couples de TAGs standards. (3) enfin une troisième méthode, utilisant la MS2, s appuie sur le principe de la méthode de dissociation compétitive d une paire [TAGref Li -TAG]+. En utilisant la méthode des ajouts dosés il est montré qu elle ne nécessite que de la disponibilité d un seul des deux TAGs stéréoisomères comme standard.Ces méthodes originales ont permis, malgré leurs limites respectives de caractériser la régiospécificité d un certain nombre de TAGs présents dans l huile de graine de Pinus Koraiensis.This thesis consisted of developing a new analytical strategy using liquid chromatography coupled with mass spectrometry (LC-MSn) to identify in oils and fats, triglycerides (TAGs) and their regio-specificity. The general analytical methodology was applied to 8 conifers seed oils, in particular, the seed oil of Pinus koraiensis. These conifer seed oils differ from common edible vegetable oils by having a series of unusual polyunsaturated fatty acids (UPIFA) with a polymethylene-interrupted (PMI) double bond system and a double bond at the 5 position which may have anti-cholesterol properties. This thesis is composed of four chapters: the two first chapters, literature review, are devoted respectively to TAGs of the 8 resinous seed oils studied and analytical techniques already used. The third chapter is dedicated to the development of a new analytical strategy combining HPLC with mass spectrometry method to identify TAGs in Pinus Koraiensis seed oil. Thanks to post column addition of silver salt, it was possible to determine the TAGs present by Ag+-NARP-LC-MS and also the fatty acids composition of the TAGs by Ag+-NARP-LC-MS2. Concerning the distinction between TAGs with the same mass, same chain length but differing positions of double bond on fatty acid chain, it was determined by chromatographic retention rules which link linearly the logarithm of retention factor of each TAG to the total carbon number or the total number of double bonds. This study has identified 22 new TAGs from a total of 58 TAGs characterized. It confirmed the knowledge that the saturated fatty acid with 17 carbon atoms is branched, not linear. It highlighted the presence of three constituent fatty acids that have never been described: 19:1, 19:2 and 24:0 in the seed oil of Pinus koraiensis. The last experimental part is devoted to the regiospecificity determination of TAGs. Three methodologies were developed. The first one used the ratios of diacylglycerol ions of TAGs but was not reliable enough. The second method used the LC-MS4 experiments (It is relevant if they have available couples of TAG standards). Finally, a third method, using MS2, based on the principle of the method of competitive dissociation of a pair [TAGref - Li-TAG] +. Using the method of standard additions it has been shown that it requires the availability of one of the two stereoisomers TAGs as a standard.These methods provide a significantly different approach to regioisomer characterization of TAGs and overcome most of the shortcomings of existing methodologies.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF