China
Africa
Explore chapters and articles related to this topic
Thin-Layer Chromatography in Plant Sciences
Published in Bernard Fried, Joseph Sherma, Practical Thin-Layer Chromatography, 2017
Rauwolfia. Most of the Rauwolfia alkaloids belong to the β-carboline type of structure. The main alkaloids, serpentine, ajmaline, and reserpine can be separated with the solvent: toluene–ethyl acetate–diethylamine (70:20:10) or heptane–ethylmethylketone–methanol (58:34:8) and detected with Dragendorff’s reagent. All Rauwolfia alkaloids show a brown color in visible light; ajmaline shows a prominent fluorescence quenching in UV light at 254 nm, and can be made visible by treatment with concentrated nitric acid.4 The use of cyclohexane–diethyl ether (3:2) and chloroform–methanol (19:1) or (9:1) on silica gel gives a good separation of six indole alkaloids from Rauwolfia cubana stem bark.16
Nonionic Polymers – the Vinyl Group
Published in Philip Molyneux, Water-Soluble Synthetic Polymers: Properties and Behavior, 1983
Examples of relevant studies on NMP are those of Takayama and co-workers212 on complexes with aminobenzoic acids; of Randall and co-workers213 on complexes with phenols; and of Hosono and co-workers214 on complexes with the alkaloid ajmaline. Heats of solution215,216 and NMR studies in solution214 have also been reported (see Tables 3 and 4).
Ablation for the treatment of Brugada syndrome: current status and future prospects
Published in Expert Review of Medical Devices, 2020
Alessandro Rizzo, Carlo de Asmundis, Pedro Brugada, Mark La Meir, Gian-Battista Chierchia
In subjects without spontaneous type 1 ECG pattern, SCB challenge is commonly used to unmask the ECG pattern. Ajmaline and flecainide are the most commonly used drugs while procainamide is considered less effective [43,46]. Ajmaline, the most effective among SCB, is an alkaloid, classified as a IA antiarrhythmic agent, found in the root of Rauwolfia serpentine which acts by changing the shape and threshold of cardiac action potentials by inhibition of various currents, including INa, Ito or rapid delayed rectifier potassium current (IKr) [47]. Flecainide is a IC antiarrhythmic agent acting on the same channels but considered less sensitive than ajmaline in BrS diagnosis [48].