Catechu Nigrum, I.C.A. Black Catechu.
Related entry: Uncaria gambier
Black catechu is an extract prepared from the heartwood of Acacia Catechu, Willd. (N.O. Leguminosae), a tree indigenous to India and Burmah. It is official in India and the Eastern and North American Colonies for use in making official preparations, for which pale catechu (gambier) is directed to be used. The bark and sapwood are stripped from the trunk, the red heartwood cut into chips and boiled in water in earthen pots. The decoction is strained and boiled down in iron pots to a syrupy consistence; this is allowed to cool and is then poured into a wooden mould lined with leaves or paper and left to harden. The resulting solid extract forms large masses, which are broken up into pieces of irregular shape and exported. Black catechu or cutch occurs in irregular dark brown or nearly black masses, to which pieces of leaves or paper are often found adhering. It is brittle, the fractured surface exhibiting numerous small cavities. It yields a reddish-brown powder, with an astringent taste.
Constituents.—The chief constituents of black catechu are catechu-tannic acid (25 to 35 per cent.), acacatechin (2 to 10 per cent.), quercetin, and catechu red; gum and colouring matter are also present in the drug. Black catechu differs from pale catechu in being devoid of a fluorescent body.
Action and Uses.—Black catechu resembles pale catechu in its properties, and is employed for similar purposes.
Dose.—3 to 10 decigrams (5 to 15 grains).