US Dispensatory, 1918.
Marrubium. Hoarhound. Horehound. Herba Marrubii. Marrube Blanc, Fr. Cod. Andornkraut, Weisser Andorn, G. Marrubio, It., Sp.—Under the title of marrubium the U. S. P. formerly recognized "The dried leaves and flowering tops of Marrubium vulgare Linné (Fam. Labiatae)." U.S. VIII. White hoarhound has a perennial, fibrous root, and numerous annual stems, which are quadrangular, erect, very downy, and from twelve to eighteen inches high. The leaves are about 2.5 cm. long, roundish-ovate, dentate or deeply serrate, obtuse, wrinkled, veined, downy above, hoary on the under surface, and supported in pairs on strong foot-stalks. The flowers are white, and in crowded axillary woolly whorls. It contains a volatile oil, resin, tannin, lignin, and a bitter principle called marrubiin by Mein. This marrubiin is slightly soluble in cold water, crystallizes from alcohol in prismatic and from ether in tabular crystals, is not precipitated by tannin, and has a very bitter and somewhat acrid taste. The fusing point of the crystals is 160° C. (320° F.), according to Kromayer. Marrubiin was afterwards obtained by Harms (A. Pharm., cxvi, 141), by Hertel (A. J. P., June, 1890), and by Morrison (A. J. P., July, 1890). It has also been studied by Matusow (A. J. P., 1897, 201). He gives to it the formula C30H43O6, and states the melting point of the purified substance to be from 154° to 155° C. (309.2°-311° F.). According to him, it is not a glucoside.
Hoarhound is tonic, and in large doses laxative. It was formerly considered a valuable deobstruent, and was recommended in chronic hepatitis, and various cachetic affections, but it exerts no specific influence over any of them, and has passed mainly from the hands of physicians into domestic use, where it is used in the form of a confection for sore throat. It is employed occasionally in bronchitis with copious expectoration. The infusion, made in the proportion of an ounce of the herb to a pint of boiling water, may be given in wine-glassful doses. Geo. M. Beringer gives the following process for Syrup of Hoarhound: Hoarhound in No. 20 powder, 200 Gm.; sugar, 750 Gm.; glycerin, 125 mils; water, a sufficient quantity to make 1000 mils.
Mix the glycerin with 375 mils of water and moisten the drug thoroughly with sufficient of the mixture, then pack lightly in a percolator and add enough menstruum to saturate and leave a layer above the drug and macerate for twenty-four hours. Then percolate slowly, using the balance of the menstruum and then warm water till extracted. Reserve the first 500 mils of percolate and evaporate the remainder to 100 mils, then add the reserve and dissolve the sugar in the liquid, using a slight heat if necessary. When cold add sufficient water to make the preparation measure 1000 mils and strain. Syrup of hoarhound so made is clear, brown in color and possesses the characteristic bitter and aromatic taste of the drug and after keeping for more than six months has shown not the least tendency to change. (Proc. N. J. Pharm. Assoc., 1909, 45-46.)
Dose, thirty grains to a drachm (2.0-3.9 Gm.).