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.
Red sanders wood is the heartwood of Pterocarpus santalinus, Linne filius (N.O. Leguminosoe), a small tree indigenous to Southern India and the Philippine Islands. During the Middle Ages it was classed as a spice and used for culinary purposes, and at one time it was supposed to possess medicinal properties; it is now employed solely as a colouring agent.
The tree is regularly cultivated in districts situated to the west and north-west of Madras. The felling of the trees is controlled by the inspectors of forests, and the revenue thus obtained is considerable. The dark red heartwood alone is exported.
Description - Red sanders wood is imported in irregular often branching billets, commonly 7 to 15 cm. thick and about a metre long, deprived of both the rugged bark and the pale sap wood. It is of a deep blood-red colour both internally and externally, the transverse section exhibiting alternating darker and lighter zones. The medullary rays are just visible under the lens; the vessels are large, mostly isolated, and connected by fine, bright red lines (wood parenchyma). The wood is very hard, but can be easily split. It is inodorous, has but a very slight astringent taste.
The red resinous colouring matter is produced in the form of droplets in all the elements of the heartwood (wood fibres, wood parenchyma, and vessels). It is readily soluble in alcohol, but only very sparingly in water, and in this respect it differs essentially from logwood, which freely yields its colouring matter to water.
In pharmacy the wood is usually employed in the form of small, hard, splintery raspings of a dull purplish red colour.
The student should observe
(a) The dull purplish red colour,
(b) The hardness,
(c) The slight solubility of the colouring matter in water.
The chief constituent of red sanders wood is santalin (santalic acid), C15H1405, which has been obtained in blood-red microscopic needles melting at 226°. It is insoluble in water, but yields a blood-red solution with alcohol, yellow with ether, and violet with caustic alkalies. Santal (Weidel, 1869), pterocarpin, and homoptero-carpin (Cazeneuve and Hugouneng, 1887, 1890) are colourless crystalline substances also contained in red sanders wood.
Red sanders wood is used solely as a colouring agent, and even in this respect it has only a limited application, as the colouring matter requires alcohol to dissolve it, and is precipitated when the alcoholic solution is diluted with water.