Colchicine red-ox chemistry revisited: Cathodic behavior and EPR observation of an intermediate radical anion

Development and optimization of a stability indicating method on a monolithic reversed-phase column for Colchicum dry extract

This article presents a method developed on a monolithic reversed-phase column for separation of related alkaloids and degradation products from colchicine in dry extract preparations from Colchicum seeds. Optimization was performed using an optimization software with variation of the pH of the mobile phase and the percentage of organic modifier. This method permits for the first time a fast separation of all alkaloids including colchiceine without prior derivatization or complexation with excellent linearity, precision and low limits of quantitation which makes it a suitable method for stability testing of extracts or drug formulations containing extracts of Colchicum seeds.

Supercritical carbon dioxide extraction of colchicine and related alkaloids from seeds of Colchicum autumnale L

A method for the extraction of the alkaloids colchicine, 3-demethylcolchicine and colchicoside from seeds of Colchicum autumnale by supercritical carbon dioxide has been established. Several parameters such as pressure, temperature, percentage of modifier and extraction time have been examined. Two extraction steps with constant carbon dioxide density (0.90 g/mL) and flux (1.5 mL/min) were required to extract the alkaloids in 110 min using 3% methanol as modifier. The quantitative determination of the alkaloids was performed by HPLC; the percentages of recovery were higher than 98% for the three alkaloids. This extraction procedure was compared with a conventional method involving maceration and sonication, and the same levels of alkaloids were obtained in each case. The supercritical carbon dioxide method is, however, very efficient, more rapid and more environmentally friendly than conventional methods.