The leaves and rhizome of Menyanthes trifoliata, Linné.
COMMON NAMES: Buckbean, Bogbean, Marsh-trefoil, Water-shamrock.
ILLUSTRATION: Bentley and Trimen, Med. Plants, 184.
Botanical Source.—This plant is perennial, has a blackish rhizome, about 5 or 6 lines in diameter, penetrating horizontally in the earth to a great distance, regularly intersected with joints at the distance of about half an inch from each other; these joints are formed by the breaking off of the old petioles and their sheaths. The leaves proceed from the end of the rhizome on long stalks furnished with broad, sheathing stipules at the base; are trifoliate, nearly oval, glabrous somewhat fleshy, slightly repand, or furnished with many irregularities at the edge, which hardly prevent them from being entire. The scape is round, ascending, smooth, about a foot high, bearing a conical raceme of flowers. Peduncles straight, supported by ovate, concave bracts. Calyx erect, somewhat campanulate, 5-parted and persistent. Corolla white; its tube short, border 5-cleft, spreading, at length revolute, and clothed on the upper part with a coating of dense, fleshy, obtuse hairs. Stamens 5, shorter than the corolla, and alternate with its segments; anthers oblong, arrow-shaped. Ovary ovate; stigma bifid and compressed. Capsule ovate, 2-valved, and 1-celled; seeds numerous and minute (L). Its flowers are flesh color or pale lilac.
History.—Buckbean is indigenous to this country and Europe, growing in spongy, boggy soils, swamps, ditches, etc., flowering from April to August. The whole plant possesses medicinal properties, but the root and leaves are the parts more generally employed. The whole plant is nearly odorless, but has a very bitter, somewhat aromatic taste. Water, or alcohol, takes up its active properties. Infusions of the leaves, saccharated by adding simple syrup, gelatinize through the presence of pectin; if the latter is removed by alcohol, no gelatinization takes place (see Amer. Jour. Pharm., 1881, p. 360).
Chemical Composition.—Menyanthes trifoliata contains a bitter, glucosidal principle, first isolated, in 1861, by Ludwig and Kromayer, and called menyanthin. Karl Lendrich, in 1892, gave an improved method of obtaining menyanthin (Archiv der Pharm., 1892, p. 38), and found it to have the formula C33H50O14. It is a neutral body of bitter taste, and yellow color, soluble in alcohol and hot water; soluble with difficulty in cold water and ether. Although menyanthin contains no nitrogen, it strangely enough responds to alkaloidal reagents, such as Mayer's solution, tannic acid, etc. Diluted alkalies or acids cause it to split into a resinous product, a laevo-rotatory sugar, and a volatile, sweetish, aromatic oil, menyanthol (C7H11O2)n, which is both an aldehyde and a phenol. Contrary to some statements, it has not the odor of bitter almond oil.
Action, Medical Uses, and Dosage.—Buckbean, when recent, and given in large doses, usually causes emesis. It is, when dried, tonic and astringent, or purgative, according to the dose. It is valuable as a tonic where digestion and blood making are impaired, and particularly when there is an associated uterine disease or irregularity, or when following the use of quinine in malarial disorders (Scudder). For this purpose, a strong tincture of the fresh leaves may be given in doses of from 1 to 10 minims. It has been given in dyspepsia, intermittent and remittent fevers, with advantage; and has been highly recommended in chronic rheumatism, hepatalgia, dropsy, worms, and some cutaneous diseases, and as a tonic in scrofula, and various cachectic affections. As a tonic, the powdered root or herb may be given in doses of front 10 to 25 grains; of the aqueous extract, 5 or 10 grains; of the infusion (made by infusing 2 drachms of the herb or root in 4 fluid ounces of water at 212° F.), a fluid ounce or two; repeating the dose of either every 3 or 4 hours. Sixty grains of the powder, or 4 fluid ounces of the infusion, produce catharsis, and sometimes emesis.