GB770542A - Improvements in or relating to the proparation of hecogenin - Google Patents

Abstract

Hecogenin is separated from a water-insoluble concentrate containing it and obtained by fermentation of the juice of the sisal plant by extraction of the concentrate with an aliphatic alcohol containing not more than four carbon atoms, heating the alcoholic extract with caustic alkali for a time sufficient to digest the coloured impurities taken up in the extract, and then precipitating hecogenin by means of water. The alcoholic extract is preferably concentrated prior to the alkali treatment until the concentration of the tottl extracted matter represents 10-35 per cent of the whole extract and then treated with caustic potash or soda (in proportion of about 0.2-1.0 to 1 part by weight of extracted material) preferably in aqueous or aqueous-alcoholic solution forming a 4-20 per cent solution of alkali. The aliphatic alcohol may contain up to 20 per cent water to increase the selectivity of the alcoholic extraction. In examples: (1) a powdered hecogenin concentrate is continuously extracted with boiling ethanol or methanol, the extract concentrated and refluxed with aqueous-alcoholic potassium hydroxide, the excess alcohol removed by steam-distillation and the precipitation hecogenin washed with hot water and dried; (2) (large-scale operation) a hecogenin concentrate is extracted as before, using aqueous ethanol, extract concentrated, solid potassium hydroxide added, mixture refluxed and then partially steam-distilled; hecogenin is then precipitated from the alcoholic residue by the addition of water, and purified by acetylation and crystallization. Specification 728,961 is referred to.