354 



SUBTERRANEAN ORGANS 



Jalap resin is an exceedingly complex mixture, the composition of which is 

 only imperfectly known. Treatment with various solvents in succession has 

 given the following results : 



Petroleum Spirit, 1/9 per cent., containing fatty acids and fats, phytosterol, 

 cetyl alcohol. 



Ether, 9-7 per cent., containing ipurganol ; after treatment with alkali followed 

 by acid, chiefly amorphous substances were obtained, together with a little 

 phytosterol, cetyl alcohol, &c. 



Chloroform, 24*1 per cent., containing /3-methylsesculetin ; after treatment 

 with alkali and acid, formic, butyric and (/-methylethylacetic acids, glucose, 

 convolvulinolic acid (C 15 H 30 3 ), and a higher homologue 

 were obtained. 



Ethyl Acetate, 22 per cent., similar in composition to 

 the chloroform extract. 



Alcohol, 38-8 per cent., by treatment with barium 

 hydroxide a water-soluble, non -purgative, ' hydrolysed,' 

 resin was obtained, which, boiled with dilute sulphuric acid, 

 gave glucose, convolvulinolic acid, ipurolic acid (also found 

 in 7. purpurea, Roth), formic, butyric and valeric acids. 



All these extracts except the petroleum spirit are purga- 

 tive, and each appears to be only partly glucosidic. Con- 

 volvulinolic acid (hydroxypentadecylic acid), and ipurolic 

 acid are crystalline ; they appear to exist in the resin in 

 the form of glucosides which can be split up by appropriate 

 treatment. 



The portion soluble in ether is assumed to be identical 

 with scammony resin. 



Good jalap should yield not less than 10 per 

 cent, of total resin when exhausted with alcohol, 

 the tincture concentrated and poured into 8 vol- 

 umes of water and the precipitated resin washed 

 and dried. Much of the drug that at present 

 reaches the market contains considerably less, 

 and its exclusion from use in making the official 

 preparations of jalap is ensured by the minimum requirement of 

 10 per cent, adopted by the British Pharmacopoeia. On the other 

 hand there seems to be little doubt that the quality of the drug has 

 deteriorated during the last twenty-five years, from 12 to 18 per cent, 

 being formerly the usual amount of resin contained in it. Under 

 exceptional circumstances. the quantity has risen in roots cultivated 

 in India to upwards of 20 per cent. 



Uses. Jalap is a powerful stimulant of the intestinal secretion, 

 producing in small doses a laxative effect, and in large doses active 

 purgation. It is much used as a hydragogue cathartic. 



Varieties. Tampico jalap is afforded by Ipomcea simulans, 

 Hanbury, a plant resembling /. Purga and growing on the eastern 



FIG. 185. Tampico 

 Jalap root. Nat- 

 ural size. 



