Extractum Taraxaci. U. S., Br. Extract of Taraxacum.
Related entries: Taraxacum
Extract of Dandelion; Extrait de Dent-de-lion, Fr.; Löwenzahnextrakt, G.; Estratto di tarassaco acquoso, It.
"Taraxacum, in No. 30 powder, one thousand grammes [or 35 ounces av., 120 grains]; Alcohol, Water, each, a sufficient quantity. Mix one hundred and twenty-five mils [or 4 fluidounces, 109 minims] of alcohol with eight hundred and seventy-five mils [or 29 fluidounces, 282 minims] of water, and, having moistened the powder with a portion of the mixture, pack it in a cylindrical percolator, then add enough of the menstruum to saturate the powder and leave a stratum above it. When the liquid begins to drop from the percolator, close the lower orifice, and, having closely covered the percolator, macerate for twenty-four hours. Then allow the percolation to proceed, gradually adding menstruum of the same strength until the drug is exhausted. Recover the alcohol from the percolate by distillation and evaporate the residue with frequent stirring, on a water bath, to a pilular consistence." U. S.
"Crush Taraxacum Root; press out the juice; allow the starchy matter to subside; decant; heat the liquid to 100° C. (212° F.), and maintain the temperature for ten minutes; strain; evaporate to a soft extract." Br.
The inspissated taraxacum juice of the former U. S. Pharmacopoeias has been superseded by the present hydro-alcoholic extract, because of the very variable quality of the former; if the root is of good quality a better extract can be made by percolation and evaporation in the usual way.
The extract made from the juice is undoubtedly stronger when prepared from the root alone than from the whole plant. It is important that the root should be collected at the right season. The juice expressed from it in the spring is thin, watery, and of a feeble flavor; in the latter part of the summer, and in autumn, thick, opaque, cream-colored, very bitter, and abundant, amounting to one-third or one-half its weight. It may be collected in August, and afterwards until severe frost. According to Squire, frost has the effect of diminishing the bitterness and increasing the sweetness of the root. An extract prepared by inspissating the juice is more efficient than that prepared in the old way by decoction. The inspissation should be effected by exposing the juice in shallow vessels to a current of warm dry air, or by evaporation in a vacuum, and should not be unnecessarily protracted. Long exposure during evaporation changes the bitterness of the juice into sweetness, which is a sign of inferiority. In the British process it is wisely directed that before the evaporation of the juice it shall be exposed for a short time to a heat sufficient to coagulate the albumen, which is then separated and rejected as useless; it is indeed injurious, by favoring decomposition. As often found in the shops, the extract is dark-colored, sweet, and in all probability nearly inert. Houlton took more than an ounce of it in a day, without any sensible effect. (P. J., i, 421.) When prepared from the root and leaves together, it has a greenish color. Brande states that one cwt. of the fresh root affords from twenty to twenty-five pounds of extract by decoction in water. The expressed juice yields from 11 to 25 per cent. of extract, the greatest product being obtained from plants collected in November, and the least in April and May. This extract deteriorates by keeping. It is conveniently given in an aromatic water.
Dose, from fifteen grains to a drachm (1-3.9 Gm.) three times a day.
The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.