This is a lofty forest tree growing wild mainly in India, Ceylon and the Philippines; a few Pterocarpus varieties also grow in tropical Africa. 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 hairy beneath; the stipules wanting. The flowers are
yellow, with red veins, papilionaceous and borne in axillary, simple or branched, erect racemes. The wood is not fragrant and does
not yield an essential oil on steam distillation. The wood is comminuted into a fine powder that is used as a red dye in a few food
products (spice blends and sauces). The wood is the only part used.
Composition
The coloring principle of red saundersissantalic acid (santalin). A new isoflavone glucoside, 4?,5-dihydroxy 7-O-methyl isoflavone 3?-O-beta-D-glucoside together with santal, liquiritigenin and isoliquiritigenin has been isolated from the heartwood of red saunders.* P. santalinus contains santalins A, B and C, but no santarubin. Savinin and calocedrin, dibenzyl butyrolactone-type lignan compounds having an α-arylidene γ-lactone structure, were isolated from red saunders.
