The root of Piper methysticum, Forster (Macropiper methysticum, Miquel).
COMMON NAMES: Ava, Kava-kava, Intoxicating long pepper, Ava pepper shrub.
Botanical Source and History.—This is a shrub about 6 feet high, somewhat resembling the bamboo in growth, a native of and common in cultivation in the South Sea Islands. It was discovered by James Cook, the celebrated explorer, in 1769, in the Tahiti Islands. The leaves (see illustration in Pharm. Jour. Trans., 1876, p. 149) are alternate, cordate, with a wavy, entire margin, and an abrupt, acute point. The petiole is about an inch long, dilated at the base, and furnished with linear, erect stipules. The veins are prominent, about 12, diverging from the base of the leaf-blade. The flowers are small, apetalous, and arranged on slender spikes. Those bearing male flowers are axillary and solitary. The female spikes are numerous. This shrub is known in its native country under the names Kava, Ava, Arwa, Ava-kava, Kava-kava, etc., and is the "Intoxicating Long Pepper," from which a disgusting drink is prepared by the natives, and even by the whites, of these islands. This drink is invariably made by chewing the root of the plant to a pulp, covering this with water, macerating a short time, and then straining it through "fow,'' a fibrous material obtained from the bark of a certain native tree. The taste is said to resemble soap-suds and tannin. (For the methods of its preparation by the natives and its uses, see an interesting illustrated paper by Dr. R. H. True, in Pharm. Review, 1896, p. 28; also see T. R. N. Morson's abstract from Mariner's History of the Tonga Islands, in Pharm. Jour. Trans., Vol. III, 1844, p. 474; and Dr. Beeman's Letters from the Fiji Islands, in the Althenaeum, 1861.) The leaf is chewed with the betel-nut, and the dried root, under the name pipula moola, forms an article of commerce in India.
Description.—The root is the part recommended for use in medicine. Of the lot inspected by us, the main root seems to have grown horizontally beneath the surface of the ground, sending up stalks at intervals of from 2 to 4 inches. Each stalk is from ½ to 3 inches in diameter at the base, and is hollow. The cavity extends through the main root, thus giving to a longitudinal section of the root the appearance of several separate roots having grown together. Externally, the main root is brown, and covered with a thin bark. From the sides and lower part are secondary roots, about ½ to ¾ of an inch in diameter. These appear to be arranged about the bases of the stalks; in some cases they are quite long, and commence to send out rootlets at a distance of 6 inches from the main root. Internally, the large root is covered with a network of fibers beneath the bark. Coarse medullary rays compose the body. The root breaks with a fibrous fracture; it is frequently much worm-eaten internally, though, to an external examination, apparently sound. After chewing a little of it, a peculiar, acrid, benumbing sensation is imparted to the parts of the mouth with which the pulp comes in contact. This property is possessed in a much greater degree by the small rootlets.
Chemical Composition.—The chief constituent of kava-kava root, amounting to 49 per cent, is starch (Gobley, 1860). It also contains about 1 per cent of a neutral, tasteless, crystallizable principle called kavahin or methysticin (Morson, 1844; Cuzent, 1860). It is hardly soluble in cold water, easily soluble in alcohol and ether. C. Pomeranz (Chem. Centralbl., 1890, p. 124) found methysticin (C15H14O5) to be the methyl ester of methysticic acid (C14H12O5) which stands in close relationship to piperic acid of Fittig and Mielck (see Piperinum). Dragendorff (Heilpflanzen, 1899) differentiates methysticin from kavahin, stating the latter to be methylene protocatechuic aldehyde (which is the chemical name for heliotropin or piperonal). An alkaloid, kavaine, was isolated in 1889 by Lavialle (Amer. Jour. Pharm., 1889, p. 136). The active principle of kava-kava consists, however, in an acrid resin (2 per cent, Gobley, 1857) which was differentiated by Lewin (Pharm. Centralhalle, 1886, p. 72) into alpha-resin, which is a strong local anaesthetic, and the less active beta-resin.
Action, Medical Uses, and Dosage.—The root of Piper methysticum has a pleasant, somewhat lilac odor, and a slightly pungent, bitter and astringent taste, which augments the salivary discharge. It has marked general and local anaesthetic properties. It has been employed as a pleasant remedy in bronchitis, rheumatism, gout, gonorrhoea, and gleet, and has also been recommended as a powerful sudorific. It appears to exert its influence more especially upon diseased mucous membranes, and may be found useful in chronic catarrhal affections of various organs, and in chronic inflammation of the neck of the bladder. The action of the root varies, according to the amount taken; in small doses, it is tonic and stimulant; while in large doses it produces an intoxication, which, unlike that from alcohol, is of a reserved, drowsy character, and attended with confused dreams. The natives who use its infusion as an intoxicating beverage for a considerable length of time, are said to become affected with a dry, scaly, cracked, and ulcerated skin, and vision becomes more or less obscured. According to Kesteven, leprous ulcerations may be produced by its habitual use. M. Dupouy, who has given considerable attention to the therapeutical virtues of this drug, arrives at the following conclusions: Given in drink, kava is a sialagogue, but is not sudorific. In medicinal doses, it acts upon the stomach, similar to the bitter stimulants, increasing the appetite, without occasioning diarrhoea or constipation, and may prevent catarrhal affections of this portion of the digestive tube. It exerts a special stimulation upon the central nervous system, differing essentially from ethylic intoxication; and, as its taste is agreeable, one soon becomes a proselyte to it. It has a very powerful action upon aqueous diuresis, and may be classed among the most efficient diuretics. It does not occasion priapism, but, on the contrary, antagonizes it. It is endowed with remarkable and prompt blennostatic properties, augmenting the discharge previous to effecting its cure. It is of undoubted efficiency in acute vaginitis or urethritis, allaying the inflammation, causing the pain during micturition to disappear, when dysuria is present, and suppressing the mucopurulent catarrh from the vesico-urethral mucous membrane. It has, over other blennostatic agents, the marked advantages of being pleasant to take, of augmenting the appetite, of occasioning neither diarrhoea nor constipation, of alleviating or entirely subduing pain during urination, of completely changing the character of the discharge, and of effecting the cure in a very short time—10 or 12 days. He can not too highly recommend its employment, especially in the treatment of gonorrhoea. Ellingwood (Mat. Med., 1898) declares it of great value in subacute and slow forms of gonorrhoea, and especially in gleet. It is a remedy for nocturnal incontinence of urine in the young and old, when due most largely to muscular weakness.
The anticatarrhal action is probably due to the resin present, and the diuretic effects to the neutral crystallizable principle, methysticin or kavain. There may likewise be present some other active principle, not yet detected, to account for certain other influences following its employment. Piper methysticum has been successfully employed in atonic dyspepsia and in neuralgic or spasmodic dysmenorrhoea. Prof. Webster (Dynam. Therap.) regards it as our most reliable remedy for neuralgia, particularly of the parts supplied by the fifth cranial nerve, as in dental neuralgia (when not due to exposure of the dental pulp), neuralgic affections of the eyes, ears, etc., and in reflex neuralgias in other parts of the body, as gastric and intestinal neuralgia, abdominal neuroses, from prostatic, urethral, or testicular disorders, and pectoral pain due reflexly to nervous dyspepsia. He also suggests its employment in renal colic. Piper methysticum has proved useful in dropsy, intestinal catarrh, and in hemorrhoids. Sixty or 70 grains of the scraped root, macerated for about 5 minutes in a quart of water, may be taken in the course of 24 hours, repeating this quantity daily, as long as required. The dose of the fluid extract of the root is from 15 to 90 minims, in a glass of water, repeating the dose every 3 or 4 hours; specific piper methysticum, 5 to 30 minims.
Specific Indications and Uses.—Neuralgia, particularly of the trifacial nerve; toothache; earache; ocular pain; reflex neuralgia; anorexia; dizziness and despondency; gonorrhoea; chronic catarrhal inflammations; vesical irritation; painful micturition; dysuria.
Related Species.—Piper Betle, Linné. An indigenous East Indian creeper, the leaves of which, together with the areca nut (also called betel nut), and the addition of lime and sometimes catechu, constitute the celebrated masticatory of the Asiatics, the richer natives adding such aromatics as cloves, camphor, cardamoms, nutmegs, etc. Betel leaf, masticated, exerts a gently stimulant and exhilarant effect, and such is its power that, when deprived of it, its habitué experiences a sense of languor and fatigue. (See an interesting illustrated article, by Dr. Rodney H. True, on the subject of betel chewing, in Pharm. Review, 1896, pp. 130 and 177.) It has several medicinal applications among the natives, being especially used to harden the gums, preserve the teeth, and sweeten the breath. It is said to improve the voice, and is reputed aphrodisiac. (For Indian uses of the drug, see either Dymock's Materia Medica of Western India, or Dutt's Hindu Materia Medica.) Piper Betle leaves are about 5 inches long, broad-ovate, obliquely heart-shaped at base, acuminate, 5 to 7-nerved, and leathery. Their upper surface is glossy. They have an aromatic, bitter, burning taste. Betel leaves contain an essential oil, the composition of which differs according to the geographical source of the leaves. Eykman (1889) found the oil from Java leaves to contain a peculiar phenol which he called chavicol (C6H4.C3H5.OH, para-allyl-phenol). The characteristic constituent of all betel oils, however, is betel phenol (Bertram and Gildemeister, 1889), an isomer of eugenol (see Oil of Cloves). Siam betel oil also contains the sesquiterpene cadinene (C15H24). (For interesting details, see Gildemeister and Hoffmann, Die Aetherischen Oele, 1899, p. 426; also see Dymock, Mat. Med. of Western India; and article under Areca).