Haematoxyli Lignum, B.P., Logwood.

Related entries: Sappan

Logwood (Haematoxylon, U.S.P.) is the heart wood of Haematoxylon campechianum, Linn. (N.O. Leguminosae), a tree indigenous to Central America, but naturalised in the West Indian Islands. The wood is exported in logs from which both the bark and sap wood have been removed. The logs are usually cut into chips, which are often moistened and exposed in large heaps, in which fermentation is allowed to take place. For medicinal use, however, the unfermented chips should be used. The wood is hard, compact, and heavy, externally of a dull orange to purplish-red colour, internally reddish-brown. The chips or coarse particles have a slight, agreeable odour, and a sweet astringent taste, and colour dilute caustic alkalies pink. Fermented logwood chips are distinguished by their darker colour and the green lustre on portions of the surface.

Constituents.—The chief constituent of the unfermented drug is a colourless crystalline body haematoxylin, of which it contains about 10 per cent. Exposed to the air haematoxylin gradually acquires a reddish colour. Its solution in ammonia, which is bluish-violet in colour, absorbs oxygen from the air, and then contains haematin-ammonia, which can be obtained as a dark green mass with metallic lustre. It is this change that takes place during the fermentation of the chips. The drug also contains tannin, resin, and a trace of volatile oil.

Action and Uses.—Logwood is used as a mild astringent in diarrhoea, especially the diarrhoea of phthisis, in dysentery, and to arrest intestinal haemorrhage. It is a useful astringent for children, with Mistura Cretae or with bismuth. It may colour the stools and urine red. The decoction or the liquid extract may be administered in mixture form; a solid extract is prepared for use in pills. The decoction is used as an injection in leucorrhoea. Preparations of logwood are incompatible with metallic salts, especially those of iron and mercury.


Decoctum Haematoxyli, B.P.—DECOCTION OF LOGWOOD.
Logwood, in chips, 5; cinnamon bark, bruised, 0.8; distilled water, sufficient to produce 100. Add the logwood to 120 of the water in a glass flask or earthen-ware vessel, boil for ten minutes, and add the cinnamon when the decoction is nearly ready; strain, and make up the required volume, if necessary, by passing distilled water through the strainer. Decoction of logwood is used in diarrhoea and for other purposes when a mild astringent is desirable. Dose.—15 to 60 mils (½ to 2 fluid ounces).
Extractum Haematoxyli, B.P., 1885.—EXTRACT OF LOGWOOD, B.P., 1885.
Logwood, in fine chips, 100; distilled water, boiling, 1000. Add the logwood to the water and infuse for twenty-four hours; then evaporate to one-half by boiling; strain, and evaporate to dryness on a water-bath, stirring with a wooden spatula. Iron vessels should not be employed in the preparation of the extract. Extract of logwood is sometimes prescribed in pills for its astringency. A little inert vegetable powder should be added to the extract, and the pills massed with syrup of glucose. They should not be made too hard or they will resist intestinal solution. Dose.—½ to 2 grammes (10 to 30 grains).
Extractum Haematoxyli, U.S.P.—Same as B.P., 1885.
Extractum Haematoxyli Liquidum, B.P.C.—LIQUID EXTRACT OF LOGWOOD. Syn.—Liquid Extract of Haematoxylon. 1 in 1.
An astringent suitable for use in mixtures against serous diarrhoea and some forms of haemorrhage. It is sometimes combined with chalk mixture, aromatic confection, or the salts of bismuth. Dose.—2 to 8 mils (½ to 2 fluid drachms).
Mistura Haematoxyli cum Catechu, B.P.C.—LOGWOOD MIXTURE WITH CATECHU.
Each fluid ounce contains 40 minims of tincture of catechu, 15 minims of aromatic sulphuric acid with a sufficient quantity of decoction of logwood. This mixture is a powerful astringent for use in dysentery, diarrhoea such as that of phthisis, and to arrest haemorrhage from the alimentary canal. Dose.—15 to 30 mils (½ to 1 fluid ounce).

The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.