Curcuma - Turmeric
Turmeric (B.P.C. 1949).
Foreign Pharmacopoeias: Ind., Belg., Chil., Fr., and Swed.
Ind. allows both dried and fresh rhizome, and specifies a volatile oil content of not less than 4 %.
It contains curcumin, a yellow pigment which dissolves in alcohol to form a deep yellow solution; alkalis change the colour to reddish-brown.
It contains also a volatile oil, starch, and resin. Protect from light.
Uses. Turmeric is used principally as a constituent of curry powders and other condiments. It has been employed in the treatment of chronic cholecystitis.
The tincture is used for the preparation of turmeric paper, and has also been used as a yellow colouring agent.
Tinct. Curcum. (Ind. P.)
Monograph Curcuma - USD 1926
Curcuma longa L. (Fam. Zingiberaceae ) The rhizome of this plant is ovate or pear-shaped, and internally of a deep yellow or orange color. The plant is a native of Southern Asia and East Indies, and is cultivated particularly in China, Bengal and Java. The best is said to come from China.
Long turmeric, representing the secondary rhizomes, is in cylindrical or oblong pieces, 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.
Round turmeric, representing the main rhizomes, 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 are derived from the same plant. 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 has been obtained by F. A. Daube, in deep yellow crystals of a high luster, by a process which may be found in the 3. 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. Analysis of the pure curcumin, of several of its salts, and of derivatives by Daube showed its formula to be C10H10O3 Gajewsky gave the formula as C16H16O4 and Jackson as C28H28O8. Ciamicin and Silber have later given the formula as C19H14O4 (OCH3)2 or C21H20O6 which has been verified by other investigators.
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.
The rhizomes are dug up at the close of the season's growth, washed and then either scalded or boiled. During this process the starch becomes more or less altered, the contents of many of the cells becoming swollen to form pasty masses which are colored yellow by the curcumin present in the cells. The rhizomes are then quickly dried in the sun.
Statements by some of the older writers as to the presence of an alkaloid in turmeric root have not been recently confirmed.
This root is largely used as a condiment in the tropical East forming the basis of the well-known curry powder. In pharmacy it is sometimes employed to impart color to ointments and other preparations. It possesses no medicinal value.*
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 cc. of, 90 per cent. alcohol, carefully adding 25 cc. 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 tubers of the Curcuma angustifolia, Roxb., and the C. leucorrhiza, Roxb., are cultivated in India for the sake of their starch and are sometimes known as East Indian Arrow Root.
* Editors note; Since the early part of the last century, turmeric was used as a liver tonic, folk remedy in the United Kingdom. No doubt, introduced by those returning from what was then Imperial India. Where it has been used for many centuries by Ayurvedic Practitioners.