This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
Kaladana consists of the dried seeds of Ipomoea hederacea, Jacquin (N.O. Convolvulaceoe), a twining plant with a large, blue corolla resembling the major convolvulus of English gardens, common in the mountains of India. It was formerly called Pharbitis Nil, Choisy, whence the official synonym (Pharbitis is said to have reference to the colour of the corolla and Nil is the Hindustani for blue; kala-dana in Hindustani means ' black seed' and has been applied to several other seeds, giving rise to much confusion).
The seeds resemble in shape the ' quarter' of an orange, there being two flat sides meeting at an acute angle and an arched back. They are dull black, about 5 mm. long and 3 mm. wide; the hilum is distinct as a brown, slightly hairy, depressed spot. A transverse section shows plaited cotyledons in which small, slightly darker resin cells may be seen. The taste is at first not marked, but is subsequently acrid.
Kaladana contains about 14 per cent, of fatty oil, about 8 per cent, of resin and a little tannin, mucilage, etc. The resin, which is the most important constituent, is insoluble in ether and is probably identical with the ether-insoluble resin of jalap.
The seeds are much used in India as a cheap and efficient laxative.
According to Fliickiger and Hanbury 1 a variety of kaladana closely resembling the official but about twice as large are used in India. Lately (1920) the seeds of Ipomoea muricata, Jacquin, have been imported as kaladana; these are imported into India from Persia and are largely used in Bombay for the same purpose; they resemble kaladana in shape but are less angular and dark brown in colour; they are also much larger, measuring 7 to 8 mm. in length and about 5 mm. in width; they are occasionally mixed with the seeds of Acacia arabica, Willdenow (N.O. Leguminosoe) which closely resemble them in size and colour, but are flattened-oval with a darker areola in the middle of each flat side. Another variety recently in commerce is smaller than the official, being only about 4 mm. long, dark grey, with a minutely but distinctly pitted surface; this variety may contain a small admixture of a nearly black Con-volvulaceous seed with a smooth surface and also of the small, yellowish brown, flat seeds of Crotalaria juncea, Linne (N.O. Leguminosoe). The seeds of Clitorea terneata, Linne (N.O. Leguminosoe) have also been found in kaladana: they resemble vetch seeds and are mottled green and brown.