Damiana consists of the leaves of Turnera diffusa, Willd., var. aphrodisiaca, Urban (N.O. Turneraceae), and probably other species of Turnera, herbs indigenous to South-Western Texas and Mexico. The leaves are light green in colour, about 10 to 25 millimetres long, and 5 to 10 millimetres broad. They are broadly lanceolate, and shortly petiolate, with a dentate margin having three to six teeth on each side. The surface is smooth, but the veins are prominent on the under surface. The drug often contains pieces of the small, reddish-brown woody stem. The odour and taste are aromatic. Examined microscopically the leaves exhibit long unicellular hairs, and cluster crystals of calcium oxalate.
Constituents.—The chief constituents are 0.5 to 1 per cent. of a greenish, volatile oil, having the odour of chamomiles, and a light-brown amorphous bitter principle, damianin. The drug also contains two resins, and 3 to 4 per cent. of tannin.
Action and Uses.—Damiana is a mild purgative and has been recommended in the treatment of sexual debility and hypochondriasis. Possibly it acts through its mildly irritant volatile oil, causing increased peristalsis and mild stimulation of the genitourinary tract during excretion, but no reliable observations have been recorded on its action. Solid and liquid extracts are prepared. Extractum Damianae is prescribed in pill form, often with phosphorus and extract of nux vomica; Extractum Damianae Liquidum is given in mixtures, sometimes with quinine and strychnine.
- Extractum Damianae, B.P.C.—EXTRACT OF DAMIANA.
- Prescribed in pill form generally with nervine tonics and aphrodisiacs, as in the case of Pilula Damianae Composita. Dose.—3 to 6 decigrams (5 to 10 grains).
- Extractum Damianae Liquidum, B.P.C.—LIQUID EXTRACT OF DAMIANA. 1 in 1.
- Prescribed in mixtures with quinine and nux vomica, or as a syrup with the glycerophosphates or hypophosphites. Dose.—2 to 4 mils (½ to 1 fluid drachm).
- Mistura Damianae Composita, B.P.C.—COMPOUND DAMIANA MIXTURE.
- Each dose of 2 fluid drachms contains 30 minims of liquid extract of damiana, 2 minims of liquid extract of nux vomica, 5 grains of calcium hypophosphite, 5 grains of sodium hypophosphite, and a sufficient quantity of chloroform water. Dose.—4 to 8 mils (1 to 2 fluid drachms).
- Pilulae Damianae Compositae, B.P.C.—COMPOUND DAMIANA PILLS.
- Each pill contains 2 grains of extract of damiana, 1/10 grain of extract of nux vomica, 1/10 grain of phosphorated suet, with chloroform, compound powder of tragacanth, and mucilage of gum acacia. Dose.—1 pill, twice or thrice daily.