Synonyms.—White Quebracho; Aspidosperma.
Quebracho is the dried bark of Aspidosperma Quebracho-blanco, Schlecht. (N.O. Apocynaceae), a large evergreen tree which abounds in the dry central and western districts of the Argentine and adjacent regions. It occurs in nearly flat pieces, from I to 3 centimetres thick, without odour, but with a very bitter and slightly aromatic taste. The outer surface is yellowish-grey or brownish, and deeply fissured; the inner surface is yellowish-brown or reddish-brown, and distinctly striate. When broken, the fractured surface displays two sharply-defined strata of about equal thickness, both of which are marked with numerous whitish dots and striae arranged in tangential lines. The fracture of the outer, lighter-coloured layer is rather coarsely granular, while that of the darker coloured, inner layer is short and splintery.
Constituents.—The bark contains the following alkaloids:—Aspidospermine, aspidospermatine, aspidosamine, quebrachine, hypoquebrachine, and quebrachamine. Commercial aspidospermine is usually a mixture of these alkaloids; dose, 1 to 2 milligrams (1/60 to 1/30 grain). The drug also contains starch, tannin, and the two sugars quebrachite and mosite.
Action and Uses.—Quebracho is a bitter, and has been given as a tonic and febrifuge. It has a marked stimulant action on the respiratory centre in the medulla, and has been used in dyspnoea associated with cardiac, or pulmonary disease; large doses may cause nausea and vomiting. Its action on the respiratory centre is so remarkable that it seems worthy of a more extended trial. It is usually administered in the form of tincture; a liquid extract (1 in 1) has also been prepared.
- Tinctura Quebrachae, B.P.C.—TINCTURE OF QUEBRACHO. 1 in 5.
- Used as a bitter and febrifuge. Dose.—2 to 4 mils (½ to 1 fluid drachm).