Senegae Radix - Senega Root. - The dried root of Polygala Senega. From North America.

Characters. - A knobby root-stock, with a branched taproot, of about the thickness of a quill, twisted and keeled; bark yellowish-brown; sweetish, afterwards pungent, causing salivation; interior woody, tasteless, inert.

Substances resembling Senega: Veratrum Viride, Arnica, Valerian, Serpentary. All have no keel.

Composition. - The active principle of senega is saponin, a colourless amorphous glucoside, C32H54O18, decomposed by HC1 into a sugar, and sapogenin (C14H12O2). Saponin is closely allied to digitonin, one of the active principles of digitalis.

Preparations.

1. Infusum Senegae

Infusum Senegae. 1 in 20. Dose, 1 to 2 fl.oz.

2. Tinctura Senegae, - 1 in 8. Dose, 1/2 to 2 fl.dr.

Action And Uses. 1. Immediate Local Action And Uses

Externally. - Applied to the mucous membrane of the nose or throat, in the form of powder (snuff), senega is a powerful irritant, causing reflex hyperaemia, sneezing, cough, and mucous flow. These effects are not employed, but are a key to its remote local action. Solutions of saponin injected under the skin are violent local irritants and general depressants; the heart, vessels, central and peripheral nervous system, and muscles being dangerously affected.

Internally. - The action of senega on the stomach and intestines is moderately irritant, large doses causing epigastric heat, sickness, and diarrhoea; and medicinal doses deranging digestion. The absence of severe general symptoms indicates the difficulty of its absorption by the stomach.

2. Action In The Blood, And Specific Action

Saponin passes through the blood to the tissues. Senega diminishes the frequency of the heart, and probably affects the circulation much like digitalis, but in a manner which is more uncertain or at least still obscure.

3. Remote Local Action And Uses

Saponin appears to be excreted in part by the bronchial mucosa, which it stimulates thus remotely as it does when locally applied. The circulatory, muscular, and nutritive activity of the tubes is increased; the mucous secretion rendered more abundant and watery; and the efferent nerves stimulated, so that reflex cough is the result. The total action is said to be expectorant, the bronchial contents being expelled with greater force, and in greater volume, i.e. more readily and easily. Senega is in common use as a stimulant expectorant in the second stage of acute bronchitis, in chronic bronchitis, and in dilated bronchi, to liquefy and evacuate the contents of the tubes or cavities, and stimulate the "weak" surface of the mucous membrane. It is manifestly contra-indicated in acute bronchitis, phthisis, and when the digestion is feeble or deranged. Saponin is probably excreted in part by the skin and kidneys, both of which it slightly stimulates, increasing the volume of urine, and its most important solid constituents.

Krameriae Radix - Rhatany Root. - The dried root of Krameria triandra. Imported from Peru.

Characters. - About an inch in diameter, branches numerous, long, brownish-red and rough externally, reddish-yellow internally, strongly astringent, tinging the saliva red.

Composition. - Rhatany root contains from 20 to 45 per cent of rhatania-tannic acid, C54H14O21 a red amorphous substance, the watery solutions of which first colour chloride of iron green and then precipitate it, but are not precipitated by tartar emetic.

Incompatibles. - Alkalies, lime-water, salts of iron and lead, gelatine.

Preparations.

1. Extractum Krameriae

Extractum Krameriae. Aqueous. Dose, 5 to 20 gr.

2. Infusum Krameriae

Infusum Krameriae. 1 in 20. Dose, 1 to 2 fl.oz.

3. Pulvis Catechu Compositus

Pulvis Catechu Compositus. 1 in 5.

4. Tinctnra Krameriae

Tinctnra Krameriae. 1 in 8. Dose, 1 to 2 fl.dr.

Action And Uses

The preparations of rhatany possess the properties of tannic acid, and may be employed for the same purposes (see Acidum Tunnicum, page 337), except that they are obviously of no use in poisoning by antimony. The drug is not extensively ordered.