Lappa (U. S. P.)—Burdock.
The root and seeds of the Arctium Lappa, Linné (Lappa officinalis, Allioni). The U. S. P. directs: "The root of Arctium Lappa, Linné and of some other species of Arctium."
COMMON NAME: Burdock.
Botanical Source.—Burdock is a well-known biennial weed, with a tapering, fleshy, brown-colored root, from 8 to 15 inches in length, throwing off slender fibers. It has a round, solid, fleshy, juicy stem, 3 feet or more in height, furrowed, hairy, and having many wide-spreading branches. The leaves are large, alternate, on very long petioles, and are nearly entire, or slightly dentated, heart-shaped, undulated, veiny, 3-ribbed at the base, and somewhat hoary and downy beneath. The flower-heads are axillary and globose; the florets, anthers, and stigmas of which are purple, and occasionally white. The involucre is composed of imbricated scales, terminating in recurved or hooked extremities, and, when in fruit easily breaks from the stalk, and is well-known as the "burdock bur," sticking to the hair or clothing of persons who come in contact with it. The fruit is a smooth, oblong, laterally compressed achenia, transversely wrinkled, with a short, rough, prickly pappus. The seeds are quadrangular.
History.—By De Candolle this plant is named Lappa minor,—by Gaertner, Lappa major; and by Lamarck, Lappa tomentosa. The plants named by these botanists are now considered as varieties only, and are all, at the present time, included under the one term Arctium Lappa, Linné. Burdock is indigenous to Asia and Europe, and grows freely in uncultivated soils, in waste places, and around dwellings in this country, flowering in July and August. The root and seeds are the medicinal parts; the root is to be collected in the spring, or the autumn of its first year, and loses four-fifths of its weight by drying. The root only is official in the U. S. P. A tincture of the seeds (Tinctura Lappae Fructus) is prepared by percolating with diluted alcohol (3 of alcohol to 1 of water) 4 ounces of the ground fruit, to obtain 1 pint.
Description.—RADIX LAPPAE. The root is long, tapering, subcylindrical, or fusiform, externally black-brown or grayish-brown, internally of a light color. It is fleshy when recent; scaly, and longitudinally corrugated when dried, and breaks with a horn-like fracture. At the top of the root the white, silky bases of the leaf-stalks may remain as a small, tuft-like crown. It has a weak, unpleasant smell. The bark has a subsaline, and the internal, spongy parenchyma a sweetish, afterward bitter, mucilaginous taste.
FRUCTUS LAPPAE, Burdock seeds.—Small, curved, compressed, angular seeds, of a dark-brown color, or spotted with black, having an oily, spicy, bitter, subacrid taste, but no odor.
Chemical Composition.—The root was quantitatively analyzed by G. A. Weckler (Amer. Jour. Pharm., 1887, p. 393), who found fixed oil (0.4 per cent), mucilage, sugar, altered tannin (phlobaphene, 0.075 per cent), inulin, resin, ash (3.67 per cent), etc. The aqueous solution of the alcoholic extract gave indications of a glucosid. The seeds were analyzed by Prof. Trimble and Mr. F. D. McFarland (Amer. Jour. Pharm., 1885, p. 127, and 1888, p.79). Moisture was 7.3 percent, and ash 5.34 per cent. Petroleum spirit abstracted 15.4 per cent of a bland, fixed oil, drying upon exposure in thin layers to the air. It has a specific gravity of 0.930, and is soluble in ether, chloroform, benzol, and hot, absolute alcohol. A crystalline, bitter substance was also obtained by extracting the drug first with petroleum spirit, then with alcohol, pouring the concentrated alcoholic solution into water, whereby resin is separated. The aqueous solution contains the bitter principle, which proved to be a glucosid devoid of alkaloidal reaction. The name lappin is applied to it. Upon hydrolysis with very dilute acid, it is decomposed into sugar and alcohol-soluble resin.
Action, Medical Uses, and Dosage.—The root is alterative, aperient, diuretic, and sudorific. A decoction of it has been used in rheumatic, gouty, venereal, leprous, and other disorders, and is preferred by some to that of sarsaparilla. It is also useful in scurvy, scrofula, etc. The seeds are recommended as very efficient diuretics, given either in the form of emulsion, or in powder to the quantity of a drachm, or, preferably, in alcoholic form, as in specific lappa officinalis. They form a good diuretic alterative, and are used in diseases of the kidneys, and to remove boils and styes on the eyelids. The action of the seeds upon the urinary tract is direct, relieving irritation and increasing renal activity, assisting at the same time in eliminating morbid products. In chronic disorders lappa may be used to remove worn-out tissues, where the saline diuretics are inadmissible. Dropsy and painful urination, due to renal obstruction, have been relieved by it. A tincture of the fresh fruit or specific lappa should be employed. It is of marked value in catarrhal and aphthous ulcerations of the digestive tract. A favorable action is obtained from it in dyspepsia. When a cachectic condition of the blood is manifest, and where an alterative is demanded, it relieves broncho-pulmonic irritation and cough. Rheumatism, both muscular and articular, when previous inflammations have left no structural alteration, are said to be benefited by the seeds. Skin diseases, depending upon a depraved state of the cutaneous tissues and less upon the state of the blood itself, are conditions in which lappa has gained a reputation. It has been particularly praised in psoriasis, its use being long-continued to produce good results. Chronic erysipelas, milk crust, and various forms of eczema have been cured with it. The cutaneous circulation is feeble in cases requiring burdock seeds. A tincture of the recent seeds may be given in doses of from 1 to 60 drops; of specific lappa officinalis, 1 to 25 drops. An ointment of the leaves, or their juice, has been used advantageously in certain diseases of the skin and obstinate ulcers. The dose of a decoction, or syrup, of the root is from 4 to 6 fluid ounces, 3 or 4 times a day.
Specific Indications and Uses.—Feeble cutaneous circulation; scaly, dry eruptions; impaired nutrition of skin; urinary irritation; psoriasis.