Curcuma. U. S. 1870. Turmeric. Curcuma longa L. (Fam. Zingiberaceae.)—The rhizome of this plant is perennial, ovate or pear-shaped, and internally of a deep yellow or orange color. The plant is a native of Southern Asia, and is cultivated particularly in China, Bengal and Java, whence the root is exported to London, about 2,400,000 Kg. being shipped annually. The best is said to come from China.
The dried rhizome (Safran des Indes, Souchet des Indes, Fr.; Kurkuma, Gelbwurzel, G.; Curcuma, It., Sp.; Zirsood, Arab.; Huldie, Hindoo) is in cylindrical or oblong pieces (Curcuma longa), from 0.5 to 1.5 cm. in thickness, distinctly annulate, tuberculated, somewhat contorted, externally yellowish-brown or greenish-yellow, internally deep orange-yellow, hard, compact, breaking with a fracture like that of wax, and yielding a yellow or orange-yellow powder. Another variety, Curcuma rotunda, or round turmeric is ovate or pear-shaped, about the size of a pigeon's egg, and marked externally with numerous annular wrinkles. Sometimes it comes cut into two transverse segments. The two varieties have a close resemblance in sensible properties, and are derived from the same plant, though formerly ascribed to different species. The odor of turmeric is peculiar; the taste warm, bitterish, and feebly aromatic. It tinges the saliva yellow. Analyzed by Pelletier and Vogel, it was found to contain lignin, starch, a peculiar yellow coloring matter called curcumin, a brown coloring matter, gum, an odorous and very acrid volatile oil, and a small quantity of calcium chloride. Curcumin was obtained, mixed with a little volatile oil (about 1 per cent.), by digesting the alcoholic extract of turmeric in ether, and evaporating the ethereal tincture. It has been obtained by F. A. Daube, in deep yellow crystals, of a high luster, by a process which may be found in the A. J. P. (1871, 308). C. L. Jackson and Menke have submitted turmeric root to a thorough examination, and give the following results: The turmeric oil was first removed from the ground root by treatment with ligroine, then the curcumin mixed with a large quantity of resin is extracted with ether, and finally purified by crystallization from alcohol. The oil extracted by ligroine was dark yellow, and amounted to 11 per cent. of the root. The purified curcumin amounted to 0.3 per cent., and melted at 178° C. (352.4° F.). Analyses of the pure curcumin, of several of its salts, and of derivatives, show its formula to be C10H10O3. It is brown in mass, but yellow in the state of powder, without odor or taste, insoluble in benzin, scarcely soluble in water, but very soluble in alcohol, ether, and the oils. It is a diatomic monobasic acid. When treated with weak oxidizing agents it yields vanillin. The alkalies rapidly change its color to a reddish-brown, and paper tinged with tincture of turmeric is employed as a test of their presence. The paper is rendered brown also by boric acid, which it thus serves to detect. When treated with a mixture of sulphuric and boric acids it yields a product called rosocyanin, because it dissolves in alcohol with a fine red color, and is turned blue by alkalies. Its alcoholic solution produces colored precipitates with lead acetate, silver nitrate, and other salts. Turmeric is used for dyeing yellow, but the color is not permanent. James Cook has found in turmeric an alkaloid, which forms crystallizable salts with sulphuric and nitric acids, and, separated from these acids by ammonia, yields a semi-crystalline precipitate. He observed also indications of a second base. (P. J., Nov., 1870.) Ivanow Gajewaky also states that there is an alkaloid in the root. (Pharmacographia, 641.)
This root is a stimulant aromatic, bearing some resemblance to ginger in its operation, and is much used in India as a condiment, the so-called curry powder. It is a constant ingredient in the curries so generally employed in the East. In former times it had some reputation in Europe as a remedy in jaundice, but its medicinal action was purely imaginary, based on the old doctrine of signatures, and at present it is employed only to impart color to ointments and other preparations.
Turmeric, when used as an adulterant, may be detected by means of a mixture of boric and sulphuric acids, but according to A. E. Bell, a much better test is afforded by the use of the reagent made by dissolving 1 gramme of diphenylamine in 20 mils of 90 per cent. alcohol, carefully adding 25 mils of pure sulphuric acid. To a little of the suspected powder, placed on a slide, a drop of the reagent is added with a glass rod. Spots of a fine purple color immediately develop, which may be readily recognized with the microscope.
Turmeric paper, used as a test, is prepared by the method described in the appendix of the U. S. P.
The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.