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.
The dried root and stem of Ipomoea Turpethum, Robert Brown (N.O. Convolvulaceae), a native of India, Ceylon, the Malay Archipelago and N. Australia.
Turpeth occurs in pieces of very varying length and thickness; they are often 10 to 20 cm. long and 1 to 5 cm. wide, deeply wrinkled longitudinally, and of a dull grey or brown colour; sometimes the bark has been slit on one side and the central wood removed. Fracture short, the wood in old specimens in several concentric circles; vessels very large; medullary rays wide; in the bark resin cells and frequently abnormal wood bundles. Odour slight, taste nauseous but slowly developed.
Turpeth contains from 5 to 10 per cent. of resin, part of which is soluble and part insoluble in ether. The ether-soluble resin is a mixture of a- and β-turpethein, the ether-insoluble resin is turpethin. Turpeth resin has not yet been thoroughly examined; a-turpethein appears to be a rhamnoside; β-turpethein a glucoside. Further research will probably show a complex composition analogous to that of scammony resin, jalap resin, etc.
The drug has long been used in India as a purgative.