Santalum Rubrum (U. S. P.)—Red Saunders.
The wood of Pterocarpus santalinus, Linné filius.
COMMON NAMES AND SYNONYM: Red sounders, Ruby wood, Red sandal-wood; Lignum santalinum rubrum.
ILLUSTRATION: Bentley and Trimen, Med. Plants, 82.
Botanical Source.—This is a lofty forest tree. The leaves are alternate, stalked, ternate, and rarely pinnate; the leaflets alternate, petiolate, the uppermost larger, ovate-roundish or oblong, entire, emarginate or retuse, smooth above, and hoary beneath; the stipules wanting. The flowers are yellow, with red veins, papilionaceous, and borne in axillary, simple or branched, erect racemes. Bracts none. Calyx brown and 5-cleft. Stamens 10, combined into a sheath, split down to the base on the upper side, and half-way down on the lower. The legume is roundish, long-stalked, falcate upward, compressed, smooth, and keeled on the lower edge; the keel is membranous and undulated. Seed solitary (L.).
History and Description.—This is a large forest tree inhabiting Ceylon and the mountains of the opposite Coromandel coast on the Indian continent. Only in the Madras Presidency does it grow wild. The wood is the official Red Saunders, or Red sandal-wood. It is "a hard, heavy, dark reddish-brown, coarsely splintery wood, deprived of the light-colored sap-wood; usually met with in chips, or as a coarse, irregular, brownish-red powder, nearly inodorous and nearly tasteless. Red Saunders does not impart any red color to water when macerated with it"—(U. S. P.). Other dye-woods generally communicate their color to water, which is not the case with red saunders; the latter, however, imparts to alkaline solutions, ether, and alcohol, a scarlet color. The alcoholic solution produces with solutions of lead a violet-colored, with corrosive sublimate a scarlet, and with sulphate of iron a deep-violet, precipitate.
Chemical Composition.—The coloring principle of red Saunders is santalic acid (santalin), discovered by Pelletier. It is a red, tasteless, and odorless, crystalline powder, insoluble in water, soluble in ether, with yellow color, and in alcohol, with blood-red color (L. Meyer. 1848). It likewise dissolves in alkalies and acetic acid, but not in essential oils. H. Weidel (1869) obtained a similar substance, santal (C8H6O3), by extracting the wood with boiling alkaline water, precipitating with hydrochloric acid, and recrystallizing from alcohol. The yield was 0.3 per cent. Cazeneuve and Hugounenq (Jahresb. der Pharm., 1887, p. 159; and 1889, p. 127) digested the powdered wood with milk of lime, extracted the coloring substance with ether, and crystallized from alcohol. Carbon disulphide differentiated the product obtained into insoluble pterocarpin (C20H16O6) and soluble homo-pterocarpin (C24H24O6). Both substances are probably orcin-derivatives (see Lacmus). A small amount of tannin is contained in red Saunders.
Action and Medical Uses.—Tonic and astringent. Formerly used for these indications, but at present employed only for coloring tinctures, etc.
Related Wood.—CAM WOOD. Red dye-wood from Baphia nitida, De Candolle (Nat. Ord.—Leguminosae). Western Africa. It scarcely colors water, but readily gives its red color to alkalies and alcohol. The coloring principle is thought to be identical with santalin.