Isolement de xanthones et coumarines inhibitrices de l'acétylcholinestérase, respectivement à partir de "Gentianella campestris" (L.) Börner et "Gentianella amarella" (L.) Börner ssp. "acuta" (Michx.) J.M. Gillett (Gentianaceae), et "Peucedanum ostruthium" (L.) Koch (Apiaceae)

Lors d'un criblage visant à détecter des extraits végétaux présentant une activité inhibitrice de l'acétylcholinestérase, trois espèces se sont révélées significativement actives; deux Gentianaceae: "Gentianella campestris" et "Gentianella amarella" ssp. "acuta", et une Apiaceae: "Peucedanum ostruthium". Les composés d'intérêt ont été isolés essentiellement par chromatographie de partage centrifuge. Dix xanthones - dont deux nouvelles, notamment une xanthone dimérique - ainsi qu'un flavonoïde C- glycosylé ont été caractérisés à partir des deux espèces de gentiane. De la même manière, le fractionnement bioguidé de l'extrait de racines de "Peucedanum ostruthium" a conduit à l'obtention de cinq coumarines et d'une chromone. Parmi les dix-sept composés isolés, une xanthone - le triptexanthoside C - et trois coumarines ont montré une inhibition de l'enzyme particulièrement intéressante. L'ostruthol s'est notamment révélé dix fois plus puissant que la galanthamine lors de tests "in vitro", activité confirmée " in vivo" chez la souris

Le soleil à l'officine (bronzage et produits naturels)

STRASBOURG ILLKIRCH-Pharmacie (672182101) / SudocSudocFranceF

Phytothérapie et dermatite atopique

STRASBOURG ILLKIRCH-Pharmacie (672182101) / SudocSudocFranceF

Traitements alternatifs dans les nausées et vomissements chimio-induits

STRASBOURG ILLKIRCH-Pharmacie (672182101) / SudocSudocFranceF

Development of an Enzyme-Based Thin-Layer Chromatographic Assay for the Detection of Cyclooxygenase-2 Inhibitors

The search for new anti-inflammatory drugs with less side effects requires simple, fast and reliable screening methods. In this context, we have developed a sensitive thin-layer chromatographic (TLC) assay on silica gel plates to detect cyclooxygenase-2 (COX-2) inhibition. COX-2 catalyzes two sequential enzymatic reactions: a first oxygenation step that converts arachidonic acid into prostaglandin G2, and a subsequent reduction of prostaglandin G2 into prostaglandin H2. Our test is based on the co-oxidation during this peroxidation step of a co-substrate, N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD), leading to a blue-grey product. As a consequence, COX-2 inhibitors appear on the TLC plate after revelation as clear spots against the colored background. Parameters such as concentrations of enzyme, substrate, and chromogenic reagent have been optimized. The limit of detection was found to be below the microgram for standard COX-2 inhibitors such as celecoxib or ibuprofen. The developed TLC assay was also conclusive when applied to 60 various natural pure compounds and some complex natural extracts. Results demonstrated a COX-2 inhibitory activity mostly for triterpene and sterol derivatives. This COX-2 TLC assay appears as a suitable low-cost and reliable strategy for the screening of natural extracts to discover new anti-inflammatory compounds

Coumarins from Peucedanum ostruthium as Inhibitors of Acetylcholinesterase

Different plant extracts have been screened by thin-layer chromatography (TLC) bioautography in an effort to discover new acetylcholinesterase (AChE) inhibitors. The CH2 Cl-2 extract of Peucedanum ostruthium (L.) Koch roots exhibited significant inhibition of AChE-l activity. Active constituents were isolated by bioguided fractionation using almost exclusively centrifugal partition chromatography. Four coumarins (ostruthin, imperatorin, ostruthol, and oxypeucedanin hydrate) and a chromone derivative (peucenin) were found to inhibit AChE activity in this bioassay

Etude de la dynamique de la croissance racinaire par microspectroscopie infra rouge à transformée de Fourier chez arabidopsis thaliana

Lors de travaux précédents, nous avons montré que la spectroscopie Infrarouge à Transformée de Fourier (FTIR) est un outil puissant pour la détection de modifications de la paroi cellulaire dans différents fonds mutants chez Arabidopsis thaliana. Le but de ce projet est de mieux définir les modifications pariétales qui apparaissent au cours de l élongation cellulaire dans un organe en croissance comme la racine. Nous acquérons des spectres infrarouges le long de l axe d élongation entre la coiffe (pointe racinaire) et le premier poil racinaire. Nous avons utilisé une méthode statistique d analyse innovante par segmentation simultanée de processus multiples qui nous permet d identifier des zones homogènes dans la racine à partir des différences entre spectres infrarouges. Cette méthode permet donc de définir des nombres d ondes diagnostiques spécifiques de différents stades cellulaires dans la racine. L effet de traitements herbicides a été étudié via cette approche. Il nous ait apparu possible de voir un parallèle entre les modes d action spécifiques de ces molécules et les changements dans la segmentation de la racine. Notre approche a permis de développer un nouvel outil permettant d appréhender les modifications structurales de la paroi au cours de la croissance de la racinePrevious studies in our laboratory established that Fourier transform infrared spectroscopy is a powerful tool for the detection of primary cell wall modifications in different cell wall mutants of Arabidopsis thaliana. Our project goal is to better define cell wall modifications that appear during cell elongation in growing organs such as the root. We acquire infrared spectra along the root elongation axis from the root tip to the first root hair. . We used a innovative statistical algorithm implementing a simultaneous multiple change-point method that allows us to identify homogenous zones in the root from infrared spectra. This method permits the identification of wavenumbers specific for different developmental stages in the root. Using this approach, the effect of herbicide treatments were studied. We were able to establish a relationship between the specific action of these compounds and changes in the position of zones in the root. Our method allowed the development of a new tool that sheds light on structural modifications of the cell wall occuring during growth of the root.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Natural product inhibitors of acetylcholinesterase

Various natural products, such as physostigmine, have long been recognized as inhibitors of the enzyme acetylcholinesterase. Since the recent approval of galanthamine for the treatment of Alzheimer's disease by the blockage of acetylcholine degradation, attempts to find other inhibitors of the enzyme have multiplied, leading to promising candidates such as huperzine A. In this review, a listing is presented of natural product inhibitors, both alkaloid and non-alkaloid in origin. These have been isolated from plant, animal and microbial sources. Details of current testing methods on cholinesterases are given, including solution assays and screening techniques by TLC and HPLC

Ultra-performance liquid chromatography/time-of-flight mass spectrometry as a chemotaxonomic tool for the analysis of Gentianaceae species

Introduction - The segregation between the genera Gentians and Gentianella among the Gentianaceae family is poorly defined. In order to clarify the classification of these genera, some researchers have tried to incorporate data about the chemical constitution, but this has not yet been achieved in a comprehensive way. Objective - To develop a fast and reproducible analytical method for the observation of characteristic fingerprints of secondary metabolites of each genus. Methodology - Seven species were investigated, three Gentianella and four Gentiana selected for their close taxonomic links within each genus. Ten xanthones previously isolated from one of these species were used as chemotaxonomic markers. A UPLC/ESI-TOF-MS method was developed to analyse the methanolic extracts. Results - The UPLC/TOF-MS provided clear metabolic fingerprints and elemental composition of the compounds. The profiles of the three Gentianella species were strikingly similar. On the contrary, metabolic profiles of Gentians species were very different from the Gentianella chromatograms and also from each other. Several compounds were unique to each genus and therefore could be used as biomarkers. Conclusion - UPLC/TOF-MS can be applied as a chemotaxonomic tool for the rapid screening of Gentianaceae species and for the distinction between closely related taxa from the Gentianaceae family