Source, Etc

Cutch is an extract prepared from the heartwood of Acacia Catechu, Willdenow (N.O. Leguminosoe), a tree of medium size common in India and Burma. It yields a valued timber, and also an astringent bark that is used for tanning.

This drug must be carefully distinguished from the foregoing (gambier), which is official under the name of catechu. The two substances are quite distinct, and that obtained from Acacia Catechu is to be regarded as true catechu. To avoid confusion it would be well to adhere to the terms ' gambier ' and ' cutch ' for the two drugs, thus avoiding the use of the term ' catechu,' which has been applied to both.

Cutch has long been used in India as a masticatory, but it was not introduced into Europe till the latter half of the seventeenth century.

To obtain the drug the tree is felled, the bark and sapwood stripped from the trunk, the dark red heartwood cut into chips and boiled in water in earthen pots. The decoction is then strained and boiled down in iron pots with continual stirring until it attains the consistency of syrup. When sufficiently cool to handle, the extract is spread upon leaves arranged within a wooden frame or mould and left for the night. In the morning the cutch is dry, and forms brick-like masses weighing about 20 kilograms, which are broken up for the market.

Description

Cutch occurs in nearly black masses, the outer portions of which are hard and brittle, but the interior often still soft. It breaks easily, the fractured surface having a dull gloss, and containing a number of small cavities. It yields a dull brown powder and has no odour, but an astringent and subsequently sweetish taste. When macerated with cold water it forms a brown magma, which exhibits under the microscope numerous minute crystals similar to those found in gambier. Boiling water dissolves it almost entirely but on cooling deposits a crystalline sediment.

Constituents

Cutch closely resembles gambier in chemical composition. It contains as principal constituents catechutannic acid and acacatechin, but the former is usually present in much larger quantity than the latter. Acacatechin differs from the catechin of gambier in its formula, C15H1406,3H10, and melting point. The drug contains in addition catechu-red and small quantities of quercetin, but is free from the fluorescent substance that is present in gambier. Although the two drugs, gambier and cutch, as usually found on the market have little resemblance to one another, this is due solely to the manner of preparation, the syrupy liquor being in the case of gambier allowed to crystallise. This method is sometimes pursued in India with cutch, and the resulting drug, ' katha,' then closely resembles gambier, but can always be distinguished from it by the absence of the fluorescent substance.

Trimble (1888) found three samples of cutch to have the following composition: -

Catechin ...

2

to

10

per cent.

Catechutannic acid

25

to

33

,,

,,

Gum ...

20

to

29

,,

,,

Ash ...

2

to

3

,,

,,

Moisture ...

12

to

25

,,

,,

Colouring matter, etc.

21

to

25

,,

,,

Good cutch contains from 10 to 12 per cent, of catechin, whereas katha contains about 50 per cent.

Uses

Cutch is employed chiefly in the dyeing and tanning industries, especially in the former, the amount of colouring matter it contains often rendering it more suitable for dyeing than gambier.

Varieties

Similar extracts are also prepared from other substances and called ' cutch '; thus mangrove cutch is obtained from the bark of Ceriops candolleana, Arnold (N.O. Rhizophoreoe), which contains 42 per cent, of tannin.