Method for isolation of cytisine

The invention concerns a method for isolation of cytisine from plant material. The method according to the invention, consists in extraction of the plant raw material by lower alcohol, acidified with mineral acid to pH within a range 1.5-3.5. The combined alcohol-aqueous extracts are concentrated under vacuum distillation till the alcohol is eliminated and after filtration they are extracted with chloroform, methylene chloride, butyl acetate or normal butanol in a ratio of 1:1. The purified from ballast substances acid aqueous concentrate is alkalized to pH 9-12 with alkaline hydroxide or ammonium hydroxide and the resulting alkaline aqueous concentrate is extracted at least twice with chloroform, methylene chloride, butyl acetate or normal butanol in a ratio of concentrate:extractant of 1:5 to 1:10. The combined organic extracts are evaporated to dryness, then acetone or ethyl acetate are added to obtain a suspension which is allowed to crystallize completely at 5-10° C., then it is filtered and dried. The isolated product is with a high purity and yield.