GB804232A - Improvements in or relating to the production of sennosides from folia sennae or folliculi sennae - Google Patents

Abstract

Sennosides are obtained from folia sennae (senna leaves) or folliculi sennae (senna pods) by extraction with an aqueous water-soluble solvent medium, e.g. containing 5 to 50 per cent water when folia sennae and 30 to 80 per cent water when folliculi sennae is extracted, the organic constituent thereof being selected from the group consisting of aliphatic monohydric alcohols, e.g. methanol, ethanol, propanol or isopropanol, ketones, e.g. acetone, and cyclic ethers, e.g. dioxane or tetrahydrofuran, concentrating the extract, and slowly precipitating the sennosides from the concentrated extract with an aqueous or non-aqueous organic solvent selected from the said group. The extract may be filtered, concentrated to an amount 4 to 5 per cent of its volume in a vacuum of 10 to 40 mm. mercury while maintaining the temperature immediately ambient to the extract at a maximum of 40 DEG C., the concentrate agitated with an adsorption agent, e.g. talc, activated carbon, kieselguhr, active bleaching earth, bolus alba, or animal charcoal, and then filtered. The organic solvent selected from the said group is slowly added to the filtrate to precipitate the water-soluble sennosides without coagulation, the solvent concentration of the resultant solution being within the range 60 to 90 per cent in the case of a monohydric alcohol and 70 to 95 per cent in the case of any other of said organic solvents. The precipitation may be aided by addition of adsorption agents to the aqueous extract or concentrate in which case purification, e.g. filtration, of the extract or concentrate prior to the addition of the organic solvent is not necessary. The precipitate is filtered, washed with water, dissolved in excess water, and again precipitated with an adsorption agent.