N. o. C0NV0LVULACE2E. 883
water, and taken with the addition of rock salt and ginger or sugar and black pepper. Roxburgh wrote in his Flora Inrliea of this drug that " the bark of the root is by natives employed as a purgative, for which they use it fresh, rubbed up with milk. About G inches in length of a root, as thick as the little finger, they reckon a common dose."
Mr. T. N. Mukharji suggests that the uncertain action of the drug, purchased from the bazar, may be due to the admixture of the roots of Ipomcea bona-nox. The two roots, when dry, cannot be easily distinguished from each other. The plants, however, though resembling each other, can be easily identified. I. bona. noxhasa round stem, while that of I. Turpethum is ribbed. The flowers and seeds of I. bona-nox are also larger than those of L Turpetham.
Tnrpethin, C 7o - H 128 36 , the glucoside of the roots of Ipomcea turpetham, is an amorphous, yellow powder, colourless, in thin layers, and melts at 146 # 8° (corr); it has a rotatory power of— 30' 14°, and is sparingly soluble in chloroform, soluble in alcohol and acetic acid. When treated with alkalis, it yields turpethic acid, a yellow, hygroscopic mass. By oxidation with nitric acid, turpethin yields oxalic, isobutyric, and sebacic acids and carbonic anhydride, whilst potassium permanganate oxidises it to oxalic, isobutyric, and turpe- tholic acids. When hydrolysed with mineral acids, it yields isobutyric acid (I mol.), turpethole, C x6 H 30 O (? C 1(J H 30 0) 3 , a substance forming feathery, interlaced crystals and melting at 8576° (I mol), glucose (3 mols.), and a viscid, liquid acid, which was not isolated, but gave a silver salt, Ci 5 H 27 5 Ag,
Turpetholic acid, C l6 H 32 + is obtained, as mentioned, and also by the action of alkalis or their carbonates on turpethole. It forms a hard, white, crystalline mass, melts at ,88*4°, and is soluble in alcohol, sparingly soluble in ether ; turpethole seems to be the anhydride of turpetholic acid.— J. Ch. S. 1893, A. I. 424.
Turpethin is identical with jalapin in percentage composition ; when treated with baryta water, turpethic acid is formed, which is colourless and not volatile with steam.— J. Ch. S. 1896, A. I. 38.
The rhizome contains a glucosidal resin, named turpethein, soluble in pure ether. This is separable by light petroleums spirit into a soluble glucoside, a— turpethein, and a sparingly soluble body, b— turpethein. a— Turpethein is soluble in baryta water, and yields, when hydrolysed, the non-volatile fatty hydroxy-acid, C 16 H 32 3 , identical or isomeric with jalap- pinio ipomeolic, and tampicolic acids. It also yields a volatile fatty acid of C s series, probably one of the valeric acids. The sugar formed is rhamnose. b— Turpethein, when hydrolysed, gives a non-volatile, higher fatty acid, rhodeose, and dextrose.— [J Ch. T. May 31, 1907, p. 550],
