Mentha Piperita. U. S. Peppermint. Menth. Pip.
"The dried leaves and flowering tops of Mentha piperita Linné (Fam. Labiatae)." U. S.
Brandy Mint; Menthe poivrée, Fr. Cod.; Folia Menthae Piperitae, P. G.; Pfefferminzblätter, Pfeffermunze, G.; Menta piperita, It., Sp.
The genus Mentha comprises at least fifteen species, of which there are also a great many varieties. Some of the mints have been in use for culinary and medicinal purposes since antiquity, but no well defined distinction is made as to just what plants were employed. It is stated that M. piperita L. (1753), also Smith (1800)—the most important member of this genus, was long ago cultivated by the Egyptians. It is mentioned in the Icelandic Pharmacopoeia of the thirteenth century. Peppermint is now grown in considerable amounts in Europe, North America, and Eastern Asia. It is also found growing wild in ether parts of the world, as South America and Australia. The oldest existing peppermint district is in the neighborhood of Mitcham (Surrey), England. In some parts of the United States, especially in Michigan, the western part of New York, Ohio and Indiana, it is largely cultivated. On the continent of Europe other species of Mentha (particularly M. arvensis. grow with M. piperita, deteriorating the product. In America other plants (as Erigeron canadensis and Erechthites hieracifolia. cause the same trouble. Besides M. piperita other species are cultivated, as some Asiatic varieties of M. arvensis, M. spicata, M. longifolia (var. undulata), M. gentilis, M. dalmatica, and M. Pulegium. Miss Henkel reviews the situation regarding the cultivation of peppermint in the United States and describes the three kinds of mint grown for the production of peppermint oil: Mentha piperita L.; Mentha piperita vulgaris Sole, and Mentha piperita officinalis Sole. (Bul. Bur. Plant Ind., U. S. Dept. Agric., No. 90, 1906.) A comprehensive article on the cultivation of peppermint in Japan is that by Inouye in Schim. Rep., November, 1908, p. 199. Peppermint has recently been successfully grown in Wisconsin. (Paint, Oil and Drug Rev., xliv, p. 18.) The cultivation of peppermint is a growing industry on the reclaimed lands of Louisiana. (Spatula, xvii, p. 18.) Great interest recently has been taken in the cultivation of peppermint in Germany. (See Thorns in B. P. G., xx, p. 244; Arb. Pharm. Inst. Univ. Berl., viii, p. 93.) Mitlacher reports on the cultivation of peppermint in Austria and outlines methods for its culture on a large scale. (Ph. Post, xliv, p. 215; Zeit. Oest. Apoth. Ver., 1, p. 422.) It has been repeatedly pointed out that the essential oil-bearing plants of the Labiates are very capricious and constantly changing character with change of soil and climate. For an account of the cultivation of peppermint in Russia, see Proc. A. Ph. A., 1902, 831.
Peppermint is a perennial herbaceous plant, producing creeping stolons. The steins are quadrangular, channelled, purplish, somewhat hairy and branching towards the top. The leaves are opposite, petiolate, ovate, sharply seriate, pointed, smoother on the upper than on the under surface, and of a dark green color, which is paler beneath. The flowers are small, purple, and in terminal obtuse spikes, interrupted below, and cymosely arranged. Late in the season, the growth of the lateral lower branches often gives to the inflorescence the appearance of a corymb. The calyx is tubular, often purplish, furrowed, glabrous below, and five-toothed, the teeth being hirsute. The corolla is purplish, tubular, with its border divided into four segments, of which the uppermost is broadest, and notched at its summit. The four short stamens are concealed within the tube of the corolla; the style projects beyond it, and terminates in a bifid stigma. The plant should be cut for medicinal use in dry weather, in August, about the period of the expansion of the flowers. John C. Umney points out differences between white and black peppermint, in P. J., 1896, 123. For a paper on the histology of powdered peppermint by Smith Ely Jelliffe, see D. C., 1899, 252.
Properties.—It is officially described as follows : "Leaves more or less crumpled and frequently detached from the stems; stems quadrangular, from 1 to 2 mm. in diameter, glabrous except for a few scattered deflexed hairs; leaves when entire ovate-oblong to oblong-lanceolate, petioles from 4 to 15 mm. in length, slightly pubescent, laminae from 1 to 9 cm. in length, acute and sharply serrate, light green to purplish-brown, upper surfaces nearly glabrous, lower surfaces glandular hairy, especially on the veins; flower-whorls in oblong or oval spikes which are usually compact, or somewhat interrupted at the base, from 1 to 1.5 cm. in breadth, rounded at the summit, and in fruit attaining a length of from 3 to 7 cm.; bracts oblong-lanceolate, very acuminate, 7 mm. in length; calyx tubular, equally 5-toothed, pubescent and glandular-punctate, often dark purple in color; corolla tubular-campanulate, 4-cleft, about 3 mm. in length and often light purple; stamens 4, short and equal; nutlets ellipsoidal, about 0.5 mm. in diameter, blackish-brown; odor aromatic, characteristic; taste aromatic, pungent, followed by a cooling sensation in the mouth." U. S.
The morphology of Mentha piperita and other species of Mentha are discussed by Eriksson in B. P. G., xviii, p. 244. The herb, both in the recent and in the dried state, has a peculiar, penetrating, grateful odor. Peppermint is quite frequently contaminated with spearmint and in one instance the leaves of belladonna were found. The latter, while no doubt accidental, shows the necessity for the examination of crude drug's generally. (Pharm. Prax., iv, p. 38.) There is sometimes difficulty in distinguishing between the leaves of M. piperita and those of M. spicata. According to Joseph Schrenk, crystals can always be found in the glandular hairs of the peppermint, but are absent in those of the spearmint. The crystals are doubly refractive, and so transparent that sometimes a polariscope is necessary for their easy detection. These crystals have been thought to be menthol, but they seem not to dissolve in alcohol, and are probably hesperidin.
The medicinal properties depend on a volatile oil, of which from 1 to 1.25 per cent. can be obtained from the herb. The leaves are said to contain a little tannic acid. The virtues of the herb are imparted to water, and more readily to alcohol.
Uses.—Peppermint is an aromatic stimulant, much used to allay nausea, relieve spasmodic pains of the stomach and bowels, expel flatus, or cover the taste or qualify the nauseating or griping effects of other medicines. The medicine is rarely used in infusion. (See Oleum Menthae Piperitae.)
Dose, one drachm (3.9 Gm.).
Off. Prep.—Spiritus Menthae Piperitae, U. S.