Patent GB-486898-A (GB)
Title: Manufacture of substances resembling vitamines from plants
IPC: A61K31/16
Filed: 1936-12-12
Abstract: Vitamin-like substances which are probably flavanone glucosides are obtained from plant materials such as lemon and orange peel by first extracting with a water-miscible organic solvent such as alcohol or acetone, precipitating the flavanone derivative by adding an alkali or alkaline earth hydroxide, and decomposing the precipitate by means of an acid.  The precipitate may be suspended in an organic water-miscible solvent and decomposed with an acid such as carbonic acid, the flavanone derivative going into solution while the inorganic salt separates, or the precipitate may be treated with acid in an aqueous solution.  The crude solution obtained from the plant-material may be preliminarily purified by adding a heavy metal salt in an acid medium (such as lead acetate) the precipitate being discarded, and then rendering the solution alkaline, for instance by adding ammonia, whereby the heavy metal compound of the flavanone is precipitated.  This precipitate is suspended in water or alcohol and decomposed by an acid; in the former case the solution after separating the inorganic compound is concentrated and organic solvent is added to precipitate the impurities, after which the flavanone is precipitated by alkali as described above; in the latter case the alcoholic solution is precipitated in this manner. In examples, (1) comminuted lemon peel is extracted with 90 per cent alcohol, lead acetate is added, the precipitate is removed, and ammonia is added; the precipitate is suspended in 5 per cent acetic acid, neutralized with ammonia, and the precipitate suspended in absolute alcohol and decomposed with sulphuric acid the precipitate being discarded; the solution is neutralized with alcoholic soda and the precipitate is dissolved in water and alcohol is added, a resinous precipitate being separated; the resinous precipitate is dissolved in water, neutralized, and alcohol is added, the precipitate being separated; the remaining solution, together with that separated from the resinous precipitate, is cooled to -15 DEG  C. and alcoholic caustic soda is added to give a strong red colour with phenolphthalein the precipitate is separated, dissolved in N hydrochloric acid, and bicarbonate is added; a part of the flavanone separates as eriodictyol glucoside and hesperidin, and the remaining solution of eriodictyol glucoside is adjusted, filtered, and filled into ampoules; a further quantity of eriodictyol glucoside may be obtained from the precipitate separated at -15 DEG  C. by dissolving in water, precipitating with alcohol, and proceeding as described above; (2) bitter orange peel freed from the yellow layer, is comminuted and extracted with absolute alcohol and the extract is cooled and precipitated with alcoholic soda as in the later steps of example 1, that is without the lead acetate treatment.  The Provisional Specification mentions capsicum as an initial material, and describes a purification treatment in which a second addition of lead acetate is made after the neutralization of the solution from the first addition.