Source, Etc

Calumba root is obtained from Jateorhiza Columba, Miers (N.O. Menispermaceoe), a lofty climbing plant with annual herbaceous stems and swollen fleshy roots. It is indigenous to Portuguese East Africa, growing in abundance in the forests in the region of the Zambesi. The root is much used by the natives as a remedy for dysentery and other diseases, and also on account of the yellow colouring matter it contains. It was brought to Europe towards the end of the seventeenth century, and after being long neglected came at last into general use. The roots are dug in the dry season, cut into transverse slices, and dried. The drug as imported is of a dingy brown colour and has a quantity of brown powder (soil) adhering to it (' natural' calumba root). It is cleaned by washing and brushing, and is then graded for sale (' washed ' calumba root). The following description applies to the washed root, which is the official variety.

Description

Calumba root occurs in commerce in irregular, elliptical or nearly circular slices averaging about 4 cm. in diameter and 6 mm. in thickness, but often much larger and thicker. They are usually depressed in the centre on both sides, the tissue there being apparently less loaded with starch and less woody than the outer portions, and consequently contracting more on drying. The exterior of the root is covered with a thin, dark, brownish, wrinkled cork, which readily separates, disclosing the yellowish brown bark beneath. The transverse surface is of a dull greyish colour passing to greenish yellow towards the outer margin of the wood and bark. When smoothed with a knife the interior is seen to be much brighter and the section exhibits a thick bark marked with radiating lines (sieve tissue), separated by a dark line (cambium) from the large central portion (wood), in which the vessels are arranged in narrow, rather distant, radially elongated groups. The parenchyma of the wood, like that of the bark, is loaded with starch-grains which under the microscope are seen to be large (20 to 70) and mostly simple with eccentric hilum; near the cork characteristic sclerenchymatous cells with yellow, . irregularly thickened walls and containing prismatic crystals of calcium oxalate are to be found.

Fig. 152.   Calumba root. Transverse section, magnified. (Moeller.)

Fig. 152. - Calumba root. Transverse section, magnified. (Moeller).

The drug breaks with a short starchy fracture; it has a slight musty odour and a marked bitter taste.

The student should observe

(a) The yellow colour and depressed centre of each slice,

(b) The thick baric and largely developed parenchymatous tissue,

(c) The short fracture and abundance of starch.

Constituents

Calumba root contains three yellow crystalline alkaloids, viz. jateorhizine, columbamine, and palmatine, the latter in small quantity only.

The drug also contains two colourless, crystalline, non-alkaloidal bitter principles, one only of which, columbin, has been investigated; this appears to be a lactone, and yields, when treated with acid or alkali, yellow amorphous columbic acid, previously believed to be a constituent of the root. Traces of a fluorescent substance, also obtainable from columbin, are present in the drug.

In addition to these principles, mucilage and abundance of starch are present, but no tannin. The drug yields from 4 to 7 per cent, of ash.

Jateorhizine, C2oH10N05,OH, columbamine, C21H12N05,OH, and palmatine, C21H12N06,OH, are closely allied to one another and also to cor'ydaline (Corydalis tuberosa, de Candolle) and to berbe-rine, forming, like the latter, a crystalline compound with acetone.

Uses

Calumba is employed as a stomachic and bitter tonic.

Substitutes, Etc

Calumba Rhizome

This is not unfrequently present in small quantity and occasionally to a considerable amount; the pieces are narrower (often about 2 to 3 cm. wide), deeper in colour, more woody, and more conspicuously radiate; they also yield more ash (12 to 17 per cent.).

Coscinium fenestratum, Cole-brooke (N.O. Menispermaceoe). The stems are occasionally imported from Ceylon under the name of Ceylon Calumba; these may be cut into slices about the size of calumba, but are readily distinguished by their dark yellow colour, flat surface, not depressed in the centre, and hard, woody (not starchy) nature. They contain berberine (3.5 per cent.).

Frasera caroliniensis, Walter (N.O. Gentianeoe). - Slices of the root of this plant have been found substituted for calumba, but the occurrence is rare; the slices are smaller, thicker, and free from starch, but contain tannin.

Fig. 153.   Coscinium fenestratum. Transverse section of stem. Natural size. (Pharmaceutical Journal.)

Fig. 153. - Coscinium fenestratum. Transverse section of stem. Natural size. (Pharmaceutical Journal).