The dried leaves and flowering tops.
Habitat. Asia, Europe, N. America; wild in low ground, wet places; cultivated in Japan, Germany, England, Michigan, New York, etc.
Sun. Menth. Pip., Brandy (Lamb) Mint, Lammint, Herba Mentha) Piperita?; Fr. Menthe poivree; Ger. Folia Mentha) piperitae, Pfefferminzblatter.
Pi-pe-ri'ta. L. piper, pepper - peppery-mint - i. c, from its aromatic burning taste.
Pep'permint - pepper + mint - i. e., mint with pepper properties.
Plant. - Perennial herb, possibly from M. hirsu'ta, Water Mint, by cultivation; rootstock creeping, producing long suckers by which it multiplies; stem square, purplish, .6-1.3 M. 2-4°) high. Leaves, ovate-oblong, 1-9 Cm. (2/5/3 3/5") long, petiole 4-15 Mm. (1/6-3/5") long, pubescent, acute, sharply serrate, light green, purplish-brown, upper surface nearly glabrous, lower surface glandular, hairy, especially on veins; more or less crumpled and frequently detached from stems, which are quadrangular, 1-2 Mm. (1/25-1/2") thick, glabrous except for a few scattered deflexed hairs; flower-whorls in oblong (oval) spikes which are usually compact, or somewhat interrupted at base, 1-1.5 Cm. (2/5-3/5) broad, rounded at summit, and in fruit 3-7 Cm. (1 1/5 - 2 4/5') long; bracts oblong-lanceolate, very acuminate, 7 Mm. (J') long, calyx tubular, equally 5-toothed, pubescent, glandular-punctate, often dark purplish; corolla tubular-campanulate, 4-cleft, 3 Mm. (I') long, often light purple; stamens 4, short; nutlets ellipsoidal, .5 Mm. (-5V) thick, blackish-brown ; odor aromatic, characteristic; taste aromatic, pungent, followed by cooling sensation in the mouth. Powder, greenish; microscopically - fragments with subglobular, shortly and stoutly stalked oil-glands, hairs having menthol crystals in one or more of the cells. Should be collected in dry weather, Aug.-Sept., when in bloom; strongest and most pungent of all mints. Solvents: alcohol; water partially. Dose, gr. 15-60 (1-4 Gm.).
Adulterations. - Leaves chiefly of varieties of this species: (a) var. officina'lis - leaves narrower, spikes longer; (b) var. vulga'ris - leaves broader, base more rounded, spikes more blunt and close; spearmint leaves, which may readily be distinguished from peppermint which has leaves with petioles, inflorescence thicker and more crowded, flowers larger with shorter calyx-teeth, and its own distinctive odor and taste.
Fig. 339. - Mentha piperita-flowering tops.
Constituents. - Volatile oil 1 p. c. (menthol), resin, tannin, gum, chlorophyll.
Oleum Menthae Piperitae. Oil of Peppermint, official. - (Syn., 01. Menth. Pip., Peppermint Oil; Fr. Essence de Menthe poivree; Ger. Pfeff'erminzol.) This volatile oil, distilled from the flowering plant (fresh or partly dried) and rectified by steam distillation, is a colorless liquid, strong odor of peppermint, pungent taste, followed by a sensation of cold upon drawing air into the mouth; soluble in 4 vols, of 70 p. c. alcohol, showing not more than slight opalescence and no separation of oil globules, sp. gr. 0.902, laevorotatory; contains 16 constituents: at least 5 p. c. of esters, calculated as menthyl acetate, C10H19C2H3O2, and 50 p. c. of total menthol, free and as esters; also acetic and isovaleric acids, acetaldehyde, isovaleric aldehyde, amyl alcohol, pinene, phellandrene, limonene, C10H16, menthone, C10H18O, menthyl iso-valerate, menthyl ester, cadinene, C15H24, a lactone, dimethyl sulphide; the hydrocarbons holding menthol dissolved are mainly the several
Fig. 340. - Mentha piperita: flower and corolla cut open; magnified 8 diam.
terpenes (English - pinene, phellandrene, sesquiterpene; Japanese - sesquiterpene alone) with carvene odor, the higher boiling ones, C15H24, having less pleasant odor; menthol and its esters (first 2 constituents) are most important, the others occurring in small quantities, being objectionable for flavoring and removed by rectification with steam. Tests: 1. Distil oil 25 Ml. (Cc.), collect the first 1 Ml. (Cc.) and pour it on 5 Ml. (Cc.) of mercuric chloride T. S. - no white film at zone of contact in 1 minute (abs. of dimethyl sulphide, found in non-rectified oils). Should be kept cool, dark, in well-stoppered, amber-colored bottles. Dose, ej-5 (.06-.3 Ml. (Cc.)).
Adulterations. - Oil of erigeron, castor oil, oil of turpentine, oil of copaiba, oil of camphor, oil of sassafras, alcohol; the first, second, and third prevent its solubility in equal volume of alcohol (80 p. c.); the fourth gives buttery mass with sulphuric acid; oils of turpentine, camphor, and sassafras each render its action with iodine more violent, the two latter being red with nitric acid; dementholized oil (lower sp. gr.).
Menthol. Menthol, C10H19OH, official. - (Syn., Pipmenthol, Peppermint Camphor; Fr. Alcool Mentholique, Menthol Gauche, Camphre de Menthe; Ger. Mentholum, Pfefferminzkampfer, Mentha-kampfer.)
This is a secondary alcohol (stearoptene), obtained from oil of peppermint or other mint oils (Japanese and Chinese oil of peppermint - M. arven'.sis var. piperas'cens, M. canaden'sis var. glabra'ta). It is obtained by subjecting the volatile oil simply to refrigeration at - 22.2° C. ( - 8° F.), by means of ice and salt; when solidified the temperature is allowed to rise gradually, the liquid portion poured off from time to time, and the crystals deprived of oil by expression; may purify by recrystallization. It is in colorless, acicular or prismatic crystals, strong odor and taste of peppermint, with a sensation of warmth followed by cold upon drawing air into the mouth; soluble in alcohol, chloroform, ether, petroleum benzin, liquid petrolatum, fixed or volatile oils, slightly in water; alcoholic solution neutral, laevorotatory; melts at 43° C. (110° F.); triturated with an equal weight of either camphor, phenol, thymol, or hydrated chloral - mixture becomes liquid; distilled with P2O5 yields menthene, C10H18, a colorless liquid of pleasant odor. Tests: 1. Heat 2 Gm. in open dish - gradually volatilizes with residue .05 Gm. (abs. of wax, paraffin, organic substances). 2. Few crystals dissolved in glacial acetic acid 1 Ml. (Cc), + sulphuric acid 3 drops and nitric acid 1 drop - not green (abs. of thymol). Impurities: Wax, paraffin, thymol, magnesium sulphate, inorganic substances. Should be kept cool, in well-closed containers. Dose, gr. 1-2 (.06-.13 Gm.).
Preparations. - I. Leaves and Tops: 1. Spiritus Menthoe Piperita?. Spirit, of Peppermint. (Syn., Sp. Menth. Pip., Essence of Peppermint; Fr. Alcoolat (Essence) deMenthe poivree; Ger. (Englische) Pfeft'erminz (-essenz)-spiritus.)
Manufacture: Macerate for 1 hour peppermint leaves 1 Gm. in 50 Ml. (Cc.) of water, strongly express; mix oil of peppermint 10 Ml. (Cc.) in alcohol 80 Ml. (Cc), add macerated leaves, and alcohol q. s. 100 Ml. (Cc), macerate mixture for 6 hours, frequently shaking, filter. Should be kept in amber-colored bottles. Dose, ex-30 (.6-2 Ml. (Cc.)).
II. Oil: 1. Aqua Menthoe Piperitoe. Peppermint Water. (Syn., Aq. Menth. Pip.; Fr. Eau de Menthe poivree; Ger. Pfefferminzwasser.)
Manufacture: 1/5 p. c Similar to Aquae Aromaticae; triturate oil .2 Ml. (Cc.) with purified talc 1.5 Gm., recently boiled distilled water q. s. 100 Ml. (Cc), filter until clear. Dose, ℥ss-l (15-30 Ml. (Cc.)).
2. Spiritus Mentha? Piperita?. Spirit of Peppermint, 10 p. c Dose, ex-30 (.6-2 Ml. (Cc)). See above.
3. Piluloe Rhei Compositoe, e.1/13 (.005 Ml. (Cc.)) in each pill. Unoff. Preps.: Leaves and Tops: Fluidextract, dose, 3j-2 (4-8
Ml. (Cc.)). Infusion, 5 p. c, dose ℥j-2 (30-60 Ml. (Cc.)). Syrup, dose, 3j-4 (4-15 Ml. (Cc.)). Troche (each contains oil e1/7; .009 Ml. (Cc.)). Menthol: Camphorated, menthol and camphor each 47.5, alcohol 5. Inunction, 5 p. c, + hydrous wool fat 95. Compound Inunction, 5 p. c, + methyl salicylate 10, hydrous wool fat 85. Petroxolin, 17 p. c, + liquid petroxolin 83. Spray (Nebula), 2 p. c, + light liquid petrolatum q. s. 100. Compound Spray, 1 p. c, + camphor 1, methyl salicylate .5, eucalyptol .2, oil of cinnamon .2, light liquid petrolatum q. s. 100. Emplastrum Menthol (Br.), 15 p. c, + yellow wax 10, rosin 75.
Properties. - Carminative, stimulant, nervine, antispasmodic.
Uses. - Spasmodic stomach and bowel pains, flatulency, nausea, cholera morbus, diarrhoea, dysentery, colic, dysmenorrhoea, nervous headache, hiccough, heart palpitation, vomiting, as a flavoring agent; externally the oil and menthol for rheumatism, neuralgia, toothache, antibacterial.