Caffeina. Caffeine, C8H10N4O2 + H2O, official.
Coffea arabica, Ldnni, and Thea sinensis, Linne.
A feebly basic substance (alkaloid) from the seeds of the former and leaves of the latter (Theaceae), also occurring in other plants; or prepared synthetically. See page 402.
Habitat. 1. Tropical Africa (Arabia, Abyssinia, Ceylon, Mocha); cultivated in tropical countries (Java, W. Indies, S. America - Brazil (most), Guatemala (best), etc.)- 2. S. E. Asia (upper Assam, China, Japan, Java, S. United States); cultivated.
Syn. Semen Coffea; Fr. Caf6; Ger. Kaffee (bohnen), Caffeia; Caffein, Theine, Guaranine, Trimethylxanthine, Methyltheobromine; Fr. Cafeme, Theine; Ger. Coffeinum, Koffein, Kaffe'in, Thein.
Cof'fe-a. L. for coffee, after Coffee, a province of Narea, in Africa, where it grows abundantly; Arabic name of the decoction - chaubi, cave, cahua, caova.
A-rab'i-ca. L. Arabian - i. e., its chief habitat.
Plant. - Handsome shrub or small tree 3-4.5 M. (10-15°) high, by cultivation trimmed down to 1.5-2 M. (5-6°); bark smooth, gray; leaves 10-15 Cm. (4-6r) long; 2.5-5 Cm. (1-2') wide, ovate, alternate, coriaceous, glossy, entire; flowers small, fragrant, white, funnel-shape, cymes; fruit oval, 12 Mm- (1/2') long, scarlet, but purple when ripe, 2-celled, 2-seeded drupe, each seed in a parchment-like endocarp; pericarp with scanty, scarcely succulent pulp, dehiscent; seed large, solitary in each cell, rounded back, flat on ventral surface (by which they face each other), hard, bony, grayish, deep narrow fissure in centre.
Adulterations. - Seed: Inferior grades: natural discolored (yellow and brown grain); artificial colored (Prussian blue, indigo, sugar, egg-albumen) - removed by soaking in water; factitious coffee made of clay, kaolin, evaporated skimmed milk, etc. - have little taste and no groove on flat side. Ground coffee: Sometimes roasted dandelion, chicory, amylaceous roots, corn, peas, beans, acorns, wheat, rye, sweet potatoes, coffee extract, etc.
Constituents. - Caffeine 1-2.3 p. c, caffearine fat (olein, palmitin) 13 p. c, glucose, dextrin 15 p. c, proteids 13 p. c, caffeo-tannic acid, (chlorogenic, coffalic), volatile oil, citric acid, trigonelline, pectin, oxydase, moisture 12-15 p. c, ash 3-5 p. c, mocha 7-8 p. c. - K, Na, Mg, carbonates, phosphates.
Fig. 371. - Coffea arabica: A, blooming and fruiting twig; B, fruit; C, fruit, cross-section; D, fruit, longitudinal section; E, seed still partly enclosed in the parchment-like endocarp.
Caffeina. Caffeine. - This is prepared commercially almost exclusively from tea and tea-dust or sweepings, but can be obtained from a strong infusion of tea or unroasted coffee by adding lead acetate to precipitate tannin, coloring matter, etc., filtering, removing excess of lead by hydrogen sulphide, concentrating, crystallizing. It is in white, flexible, silky, glistening needles, usually matted together in fleecy masses, odorless, bitter, efflorescent, soluble in water (46), hot water (5.5), alcohol (66), chloroform (5.5), ether (530); saturated aqueous solution neutral, melts, when anhydrous, at 236° C. (167 F.). Tests: 1. Dissolve .01 GM. in hydrochloric acid 1 Ml. (Cc), add potassium chlorate .1 Gm., evaporate to dryness, invert the container over a vessel containing a few drops of ammonia water - residue purple, destroyed by fixed alkalies. 2. Aqueous solution + tannic acid T. S. - precipitate, soluble in excess of reagent. 3. Dry to constant weight loses 9 p. c.; incinerate 2 Gm. - ash .05 p. c. Impurities: Alkaloids, organic substances. Dose, gr. 1-5 (.06-.3 Gm.).
Commercial. - Tree resembles our cherry, although more delicate, grows in clusters in hilly woods, 300-600 M. (1.000-2.000°) elevation; first known in Europe, 1652, as coming from Arabia, Abyssinia, where it was popular in the 15th century. The Dutch first grew it in Europe, 1690, and introduced it into America at Surinam, 1718, Cayenne, W. Indies, 1725. There are four varieties: 1, Mocha, best, smallest, dark yellow, growing on the Arabian hills around Mocha; 2, Jam (E. Indian, Ceylon), largest, pale yellow; 3, Rio, Brazilian (W. Indian, Demerara), intermediate size, bluish or greenish-gray; 4, Liberian (C. liberica - most hardy and resistant to diseases), larger berries, finer flavor. The seeds are separated from papery endocarp by drying, passing between wooden rollers, and through a winnowing mill. In roasting at 250° C. (482° F.), the fat, sugar, and tannin are destroyed, some caffeine volatilized, and an empyreumatic volatile oil (caffeol, coffeone), or some other active principle, volatile or otherwise, is developed - losing 8 p. c. water, 9 p. c. organic matter, becoming pulverizable, more aromatic, and more soluble in water. Much care should be exercised in this process to use closed vessels and not too great heat. Caffeine exists in all plants as a complex tannoid, and as such possesses decided but different physiological activity from the free alkaloid.
Preparations. - 1. Caffeina Citrata. Citrated Caffeine. (Syn., Caffein. Cit.; Br. Caffeinae Citras, Caffeine Citrate; Fr. Citrate de Cafeine; Ger. Koffeincitrat.)
Manufacture: Dissolve citric acid 50 Gm. in hot distilled water 100 Ml. (Cc), add caffeine 50 Gm., evaporate to dryness on water-bath, constantly stirring toward the end, reduce to fine powder. It is a white powder, odorless, slightly bitter, acid taste and reaction; forms clear syrupy solution with small quantity of water, but caffeine precipitates on dilution, being redissolved by additional water; compound unstable, contains 48 p. c. of anhydrous caffeine. Tests: 1. Mix 2 Ml. (Cc.) of aqueous solution (1 in 10) with lime water (50) - clear in the cold, but turbid upon boiling. 2. Dry to constant weight - loses 5 p. c.; incinerate 1 Gm. - ash .1 p. c. Impurities: Heavy metals, tartaric acid, sulphuric acid. Should be kept in well-closed containers. Dose, gr. 2-10 (.13-.6 Gm.).
Prep.: 1. Caffeina Citrata Effervescens. Effervescent Citrated Caffeine. (Syn., Caff. Cit. Eff.; Br. Caffeinae Citras Effervescens, Effervescent Caffeine Citrate; Fr. Citrate de Cafeine Effervescent; Ger. Brausendes Koffeincitrat.)
Manufacture: Mix powdered citric acid 19.5 Gm. with citrated caffeine 4, tartaric acid 30, incorporate sodium bicarbonate
54° C. (129° F.); contains 1.9 p. c. of anhydrous caffeine.
Should be kept dry, in tightly-sealed containers. Dose, 3j~2
2. Caffeinoe Sodio-Benzoas. Caffeine Sodio-Benzoate. (Syn., Caff.
Sod. Benz.; Fr. Soude benzoate de Cafeine; Ger. Caffeino-natrium
Manufacture: Mix caffeine and sodium benzoate each 50 Gm., rub to smooth paste with alcohol q. s., dry in moderately warm place. It is a white powder, odorless, bitter, soluble in water (1.1), some caffeine separating on standing, alcohol (30), partly in chloroform; aqueous solution (1 in 20) neutral, slightly acid or alkaline, not reddened by phenolphthalein T. S.; contains 46-50 p. c. of anhydrous caffeine, C8H10N4O2, the remainder being sodium benzoate, NaC7H5O2. Tests: 1. Heat - decomposes with evolution of white vapors, carbonaceous residue effervesces with acids and colors flame yellow. 2. Aqueous solution + ferric chloride T. S. - salmon-colored precipitate; + diluted hydrochloric acid - white precipitate (benzoic acid). 3. Dry to constant weight - loses 5 p. c. Impurities: Heavy metals, readily carbonizable organic matter. Should be kept in well-closed containers. Dose, gr. 2-10 (.13-6 Gm.), in powder, capsule, effervescent draught, hypodermically (?).
Unoff. Preps.: Coffea Tosta (Roasted), containing caffeine, 1 p. c, fat, 10 p. c. Fluidextract (glycerin 6.5, alcohol 25, water 68.5). Caffeine Sodio-Salicylate, caffeine, sodium salicylate, each 50, dose, gr. 2-10 (.13-.6 Gm.).
Properties. - Tonic, stimulant, nervine, antiemetic, caffeine in small doses stimulates appetite, digestion, secretion of bile, quickens heart action, respiration, increases arterial tension, urine; normal doses, cerebral stimulant, causing nervous restlessness, wakefulness, increased mental activity. Large doses (gr. 5-10; .3-6 Gm.) produce heaviness of head, insomnia, delirium, rapid, feeble pulse, cold extremities, elevated temperature, convulsions, paralyzes cardiac muscle, but death occurs from paralysis of respiration; valuable as a hydragogue diuretic; ordinary salts not suitable for hypodermic use as they decompose by the presence of water. Caffeine sodio-benzoate as a cerebral and cardiac stimulant has the advantage of being moderately stable and non-irritating. Coffee is laxative, diuretic, antiperiodic, antiseptic. Used mostly, however, as a beverage, for which alone about 1,500,000,000 pounds (680,272,110 Kg.) are consumed annually, making 1 pound (.46 Kg.) to every living person; in the United States about 6-7 pounds (2.7-3 Kg.) per capita, in Holland 10 pounds (4.6 Kg.). Uses. - Caffeine in neuralgia or nervous headaches, diarrhoea of cholera, phthisis, cardiac and renal dropsies, lithaemia, gout, insomnia of chronic alcoholism, adynamic fevers. Toffee in intermittents, asthma paroxysms, opium narcosis, to antagonize general torpor of nervous centres. Allied Plants:
1. In addition to the official source, Coffea arabica, there are a number of species that furnish coffee, as C. mauritia'na, of Mauri-tus, C. zanguebar'ia, of Zanzibar, Mozambique, etc., and C. liber'ica, of Liberia, this last being by far the most important of the three.