This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
Senega. - The root of Polygala Senega Linne (nat. ord. Polygaleae). Synonym. - Senega Snakeroot.
United States, westward to Minnesota.
About 10 cm. long, with a heavy knotty crown, and spreading tortuous branches, keeled when dry, fleshy and round after having been soaked in water; externally yellowish-gray or brownish-yellow; bark thick, whitish within, enclosing an irregular, porous, yellowish wood; odor slight, but unpleasant; taste sweetish, afterwards acrid. Resembling Senega root. - Arnica, Valerian, Serpentaria and Green Hellebore, but none of these have a keel.
The active principle is Senegin (C32H54O18). Also called Saponin, which is found in Quillaja (q. v.). It is a colorless, amorphous glu-coside, insoluble in Alcohol, but forming a soapy emulsion when mixed with boiling water, and is decomposed by Hydrochloric Acid into glucose and Sapogenin. It exists as a white powder, which forms a soapy emulsion when mixed with boiling water. It acts like Digitonin (see p. 421), and is found in many plants.
Other roots are mixed with it.
Dose, 10 to 20 gr.; .60 to 1.20 gm.
1. Extractum Senegae Fluidum. - Fluid Extract of Senega. By maceration and percolation with Alcohol, Ammonia Water and Water, and evaporation.
Fluid Extract of Senega is used to prepare Syrupus Senegae and Syrupus Scillae Compositus.
Dose, 10 to 20 m.; .60 to 1.20 c.c.
2. Syrupus Senegae. - Syrup of Senega. Fluid Extract of Senega, 200; Ammonia Water, 5; Sugar, 700; Water to 1000. Filter before adding the Sugar.
Dose, 1 to 2 fl. dr.; 4. to 8. c.c.
3. Syrupus Scillae Compositus. - See Antimony, p. 231.
Senega is an irritant to the skin.
Alimentary canal. - Senega in large doses is an irritant here also, producing salivation, vomiting and diarrhoea. Even small doses often cause indigestion. It is absorbed with difficulty.
Circulation. - Senegin circulates as such in the blood. It arrests the heart in diastole. It is excreted by the skin, the bronchial mucous membrane, and the kidneys.
Respiration. - When the powdered root is inhaled it acts as a violent irritant to the nose, causing much sneezing and cough, together with hyperaemia and increased secretion from the respiratory mucous membrane. If senega is taken internally,' the bronchial mucous membrane is irritated because of excretion through it of senegin, which causes vascular dilatation, greater secretion, and reflexly, cough. Senega is, therefore, a stimulating expectorant.
Kidney. - It is a diuretic, because excretion of senegin through the kidneys causes irritation of them.
Senega is only used as a stimulating expectorant. It is evident that it will be useful in bronchitis, when the secretion is scanty, and when the power to cough is feeble. As it is an irritant to the bronchial mucous membrane, it must not be given in acute bronchitis, nor, on account of its gastro-intestinal action, when there is indigestion. It has been employed as a diuretic, but it is not powerful, and is uncertain.