Academic literature on the topic 'Gelsemium'

La gelsémine synthétique, principe actif majoritaire de Gelsemium sempervirens, et la glycine stimulent la biosynthèse d’alloprégnanolone dans la moelle épinière (ME) de rat. De même, les dilutions homéopathiques de gelsémine et de Gelsemium sempervirens augmentent la production d’alloprégnanolone dans la ME et le système limbique. La strychnine, qui n’induit d’elle-même aucune modification de la neurostéroïdogenèse, bloque totalement les effets stimulateurs de ces substances démontrant l’implication des récepteurs glycinergiques dans les mécanismes d’action de ces composés. Ces résultats obtenus in vitro ont été corrélés à des analyses in vivo mettant en relation l’activité de la 3a-hydroxystéroïde oxydo-réductase dans la ME avec les variations des seuils de sensibilité à la douleur. Des stratégies thérapeutiques efficaces avec les dilutions homéopathiques de gelsémine et de Gelsemium sempervirens peuvent ainsi être développées dans le cadre du contrôle de la douleur et de l’anxiété<br>Synthetic gelsemine, the major active principle in Gelsemium sempervirens composition, and glycine stimulated allopregnanolone biosynthesis in the rat spinal crod (SC). Similarly, homeopathic dilutions of gelsemine and Gelsemium sempervirens strongly increased allopregnanolone production in the SC and limbic system. Strychnine, which did not modify by itself neurosteroid formation, completely blocked the stimulatory effects induced by these substances, indicating that glycinergic receptors are involved in the action mechanisms of these compounds. These results obtained in vitro were correlated with in vivo analyses by linking the 3a-hydroxysteroid oxido-reductase in the SC with changes in thermal and mechanical nociceptive thresholds. Altogether, the data open new possibilities for the development of therapeutic strategies with homeopathic dilutions of gelsemine and Gelsemium sempervirens in the control of pain and anxiety

Discovered in 1870, in the roots of Gelsemium sempervirens, gelsemine has attracted the attention of numerous research groups over the years. Chapter 1 discusses the isolation and structure elucidation of this cage-like alkaloid, along with the synthetic strategies developed to assemble the densely functionalised hexacyclic skeleton. An overview of the project and optimisation of the synthetic route to the gelsemine core structure are presented in Chapter 2. This sequence involves a 4+3 cycloaddition, a novel access to \(\alpha\) \(\beta\)-unsaturated esters and an elimination - Michael addition step. Finally, a shortened access to the gelsemine core structure from the key step is presented yielding sufficient material for further functionalisation studies. Chapter 3 discusses two novel strategies towards the construction of the gelsemine spiro-oxindole from a key tricyclic ketone. A series of attempts at -arylation of ketones using haloacetanilide derivatives are described, culminating an unexpected one-pot indole synthesis. A spiro-oxindole synthesis is presented using a metal catalysed free-radical CH activation. Progress towards implementing this strategy on the gelsemine core structure is discussed. In Chapter 4 the functionalisation of the bicyclo3.2.1octane core structure is discussed. Selective reduction of the tricyclic ketone gives an axial alcohol that cyclises to afford a lactone as the precursor of the tetrahydropyran ring.