Imperatoria. Imperatoria Ostruthium (L.) Kch. Masterwort. Rhizoma Imperatoriae, P. G. Imperatoire, Fr. Meisterwurz, Kaiserwurz, G.—An umbelliferous plant, indigenous in Southern Europe. The root has a strong odor, similar to that of angelica, and a pungent, aromatic taste, attended by a flow of saliva, and followed by a growing warmth which remains long in the mouth. E. M. Holmes (P. J., March 17, 1877) noticed this root mixed with aconite in the London market, but this probably arose from carelessness, as masterwort is worth twice as much as aconite. A crystallizable, tasteless principle, called imperatorin, was extracted from the root by Wackenroder, and Gorup-Besanez found in the root another principle, to which he gave the name of ostruthin. Besides these two crystalline compounds, masterwort contains a volatile oil, composed of a hydrocarbon and an oxygenated compound, probably the aldehyde of angelic acid. (Wagner, J. P. C., lxii, 283.) Jassoy (Ap. Ztg., v, 150) has since investigated the substance ostruthin and gives it the formula C18H20O3. He states that it does not contain a methoxyl group but a phenol-like hydroxyl. By fusion with potassium hydroxide, it yields along with a carbonaceous residue small amounts of resorcinol and acetic and butyric acids. By the action of bromine in chloroform solution it is changed in the presence of acid sodium carbonate into tribromostruthin, C18H19Br3O3. (Schmidt, Pharm. Chem., Bd. ii, 3te Auf., 1510.) Herzog subsequently examined the rhizomes and found a substance identical with oxypeucedanin. (A. Pharm., 1908, 414.) The root of masterwort was formerly used in a wide circle of complaints with so much supposed success as to have gained for it the title of divinum remedium. It is, however, merely a stimulant aromatic, which in this country is unknown as a remedy. Its leaves are used as a potherb and to flavor cheese.
The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.