Arnicae Flores, I.C.A., Arnica Flowers.
Related entry: Arnica Rhizome
Arnica flowers (Arnica, U.S.P.) are the dried flower-heads of Arnica montana, Linn. (N.O. Compositae), a small plant indigenous to Central Europe. The flower-heads are collected entire and dried, but the receptacles are sometimes removed as they are liable to be attacked by insects. The involucre of arnica flowers consists of two rows of dark green, linear-lanceolate pubescent bracts. The ray florets number about sixteen and possess when fresh, conspicuous, orange-yellow, ligulate corollas traversed by seven to nine veins, and terminating in three teeth; during the drying these corollas shrivel very much. The disc florets are numerous and remarkable for the single row of long white barbed bristles, which crowns the fruit. The latter is five-ribbed and covered with appressed hairs. The odour is aromatic and the taste bitter and acrid. The drug should yield about 6 per cent. of ash. The flower-heads of Inula britannica, Linn., are occasionally offered as arnica flowers, but are easily distinguished from the latter.
Constituents.—The chief constituents of arnica flowers are the bitter, yellow, crystalline body arnicin; a volatile oil (0.5 to 1.0 per cent.); and the colourless, crystalline phytosterol, arnisterol.
Action and Uses.—Arnica has an irritant effect upon the stomach and intestines, and may induce paralysis of the nerve centres. It is rarely given internally, but a tincture is used, diluted with water (1 in 40), as a local application to sprains and bruises. When the skin is delicate arnica may cause extensive dermatitis, and it should not be employed if the skin is broken. Arnica flowers are used in preference to arnica rhizome in the North American Colonies.
PREPARATIONS.
- Tinctura Arnicae, U.S.P.—TINCTURE OF ARNICA, U.S.P.
- Arnica flowers, in No. 20 powder, 20; alcohol (49 per cent.), sufficient to produce 100. Average dose.—1 mil (15 minims).
- Tinctura Arnicae Florum, I.C.A.—TINCTURE OF ARNICA FLOWERS.
- Arnica flowers, in No. 20 powder, 10; alcohol (45 per cent.), sufficient to produce 100. Tincture of arnica flowers is official for use in the North American Colonies. Dose.—2 to 4 mils (½ to 1 fluid drachm).
