GB768919A - Process for the preparation of podophyllotoxin-glucoside from various species of podophyllum - Google Patents

Abstract

The invention comprises podophyllotoxin b -D-glucoside, C28H32O13, m.p. 149-152 DEG C., and a process for its isolation from Podophyllum peltatum L. or Indian Podophyllum emodi Wall by extracting the rhizome (which has been freed from ether-soluble and -chloroform-soluble resins) with a water-soluble lower alkanol, concentrating the extract, dissolving the residue in aqueous alcohol, treating the solution with tannin-precipitating agents, e.g. lead salts, ferric hydroxide, to separate the glucoside from its tannin-complex, separating from the precipitated impurities, concentrating the residual solution, diluting it with water, and extracting the glucoside from the aqueous solution with water-immiscible organic solvents which may preferably contain small quantity of water-soluble alcohols, from which the glucoside is finally obtained by evaporation of solvent. The new glucoside is soluble in water and in alcohol and by enzymatic cleavage or acid hydrolysis yields podophyllotoxin and D-glucose. In examples: (1) dried and powdered rhizomes of Podophyllum emodi Wall are extracted first with chloroform and then with methanol, the latter extracts concentrated to 1/2 volume and an equal volume of water added, tannins are then precipitated with excess lead acetate, filtrate is concentrated, extracted with chloroform, and then chloroform-ethanol from which the glucoside is isolated and then purified by chromatography on silica gel. (2) As in (1) using rhizomes from Podophyllum peltatum L., and effecting purification either as above or by partition between water and ethyl acetate.