Photo: Aloe vera 7. Preparations: Extract of Aloes - Tincture of Aloes - Tincture of Aloes and Myrrh- Glycerite of Aloes - Pills of Aloes - Compound Pills of Aloes - Pills of Aloes and Asafetida - Pills of Aloes and Iron - Pills of Aloes and Mastic - Pills of Aloes and Myrrh - Compound Decoction of Aloes - Compound Powder of Jalap - Wine of Aloes
Related entry: Aloinum (U. S. P.)—Aloin

The inspissated juice obtained from the leaves of several species of Aloe.
Nat. Ord.—Liliaceae.
Official Kinds.—I. ALOE BARBADENSIS (U. S. P.), Barbadoes aloes (Curaçao aloes), Hepatic aloes. Derived from the Aloe vera (Linné), Webb; (Aloe vulgaris, Lamarck; Aloe perfoliata, var. vera, Linné; Aloe Barbadensis, Miller).
II. ALOE SOCOTRINA (U. S. P.), Socotrine aloes, Zanzibar aloes. Derived from Aloe Perryi, Baker.

Non-Official Kinds.—ALOE CAPENSIS (U. S. P., 1870), Cape aloes, Aloe lucida. Derived chiefly from Aloe spicata, Thunberg, Aloe ferox, Lamarck, and Aloe Lingua, Linné.Gasteria Lingua, Willdenow). Various other species. probably contribute to this variety. A kind known as Jefferabad aloes enters the Bombay markets, and is thought to be derived from Aloe abyssinica, Lamarck.

Botanical Source and History.Aloe vera (Linné), Webb, grows in the East Indies and Barbary; is now cultivated in the West Indies, as well as in some of the southern sections of Europe. The stem is woody, simple, cylindrical, and short; the leaves fleshy, amplexicaul, first spreading, then ascending, lanceolate, glaucous-green, flat above, convex below, armed with hard, distant, reddish spines perpendicular to the margin, and a little mottled with darker color; the parenchyma is slightly colored brown, and very distinct from the tough, leathery cuticle. The scape is axillary, glaucous, reddish, and branched; the spike is cylindrical-ovate. The flowers are at first erect, then spreading, afterward pendulous, yellow, and not longer than the stamens (L). This plant yields the Barbadoes aloes of commerce.

Several species, formerly regarded as distinct, are now regarded as varieties of this species; among them are Aloe littoralis, König; Aloe indica, Royle, and others.

Aloe Perryi, Baker, the now recognized source of Socotrine aloes, resembles in habit the Aloe vera (Linné), Webb, but its leaves are shorter and the tube of the flowers is of a much greater length than the segments. The flowers are also borne on long pedicles and arranged in racemes much looser than those of the Barbadoes plant. The true aloes plant, and that from which the drug was formerly believed to have come, is the Aloe socotrina, which inhabits the Island of Socotra. The stem is woody, straight, 1 ½ feet high, or more, and naked below, where it is strongly marked with the scars of leaves. Leaves amplexicaul, ascending, ensiform, green, curved inward at the point, convex below, rather concave above, marked with numerous small white marginal serratures; parenchyma abounding in a bright brownish-yellow juice. The raceme is cylindrical and unbranched; flowers scarlet at the base, pale in the middle, green at the point. Stamens unequal, three of them longer than the flowers.

Aloe spicata, Thunberg, or Spiked aloe, inhabits the southern parts of Africa, where it grows in sandy soil. The stem is woody, round, and about 4 feet high, and from 3 to 6 inches in diameter; the leaves are thick, fleshy, subverticillate, broad at the base, gradually narrowing to the point, full 2 feet long, channeled, distantly toothed, and dotted with a few white spots; their parenchyma is almost colorless. The spike is a foot long, and very compact; the flowers are scarlet, horizontal, campanulate, and filled with a purplish honey. The three petals are broader, ovate, obtuse, and white, with a triple green line; the sepals are narrower, and less concave. The stamens are much longer than the perianth (L). This plant (together with others above mentioned) furnishes the Cape aloes of commerce.

There are several species which furnish medicinal aloes, but the three above named are supposed to yield the principal portion, although but two are now recognized by the U. S. Pharmacopoeia. The mucilaginous juice expressed from the parenchymatous tissue of the leaves has no remedial influences; but only that which is procured by incising the air-ducts of the leaves transversely, so that the juice may flow from them or, as stated by M. E. Robiquet, from the intercellular structure between them. M. Marais states that three distinct kinds of Barbadoes aloes have been found in commerce, two of which are probably obtained by simple exudations of the juice from the incised leaves, while the third is the result obtained by boiling the plant in water and evaporating. These three kinds may be distinguished from the other species of aloes by a common property they have of giving a perfect emulsion when triturated with a little cold water.

Cultivation and Preparation.—Of the method of obtaining Socotrine aloes little is known. In regard Barbadoes aloes, the authors of the Pharmacographia state: "In Barbadoes, where Aloe vulgaris [A. vera (Linné), Webb] is systematically cultivated for the production of the drug, the plants are set 6 inches apart, in rows which are 1 to 1 ½ feet asunder, the ground having been carefully prepared and manured. They are kept free from grass and weeds, but yams or pulse are frequently grown between them. The plants are always dwarf, never in the least degree arborescent. Almost all of those above a year old bear flowers, which, being bright yellow, have a beautiful effect. The leaves are 1 to 2 feet long; they are cut annually, but this does not destroy the plant, which, under good cultivation, lasts for several years. The cutting takes place in March and April, and is performed in the heat of the day. The leaves are cut off close to the plant, and placed very quickly, the cut end downwards, in a V-shaped, wooden trough, about 4 feet long and 12 to 18 inches deep. This is set on a sharp incline so that the juice, which trickles from the leaves very rapidly, flows down its sides, and finally escapes by a hole at its lower end into a vessel placed beneath. No pressure of any sort is applied to the leaves. It takes about a quarter of an hour to cut leaves enough to fill a trough. The troughs are so distributed as to be easily accessible to the cutters. Their number is generally 5; and by the time the fifth is filled, the cutters return to the first and throw out the leaves, which they regard as exhausted. The leaves are neither infused nor boiled, nor is any use afterwards made of them except for manure. When the vessels receiving the juice become filled, the latter is removed to a cask or reserved for evaporation. This may be done at once, or it may be delayed for weeks or even months, the juice, it is said, not fermenting or spoiling. The evaporation is generally conducted in a copper vessel; at the bottom of this is a large ladle, into which the impurities sink, and are from time to time removed as the boiling goes on. As soon as the inspissation has reached the proper point, which is determined solely by the experienced eye of the workman, the thickened juice is poured into large gourds or into boxes, and allowed to harden"—(Pharmacographia).

In Cape Colony, according to Peter MacOwan, a goat-skin is spread in a shallow depression scratched in the earth, and, the aloe leaves are radially arranged in such a manner that the juice falls into the center of the skin. When filled, the juice is poured into an iron pot and boiled, great carelessness being manifested by the operator throughout the whole process (see Pharmacographia).

Description and Tests.—ALOE BARBADENSIS (U. S. P.), Barbadoes aloes. This variety comes "in hard masses, orange-brown, opaque, translucent on the edges; fracture waxy or resinous, somewhat conchoidal; odor saffron-like; taste strongly bitter. Mixed with alcohol and examined under the microscope, it exhibits numerous crystals. Mixed with nitric acid, it acquires a red color. Barbadoes aloes is not colored, or acquires only a light bluish-green tint on being mixed with sulphuric acid and blowing the vapor of nitric acid over the mixture (difference from Natal aloes)"—(U.S. P.). Barbadoes aloes is not so bright and clear as the Socotrine variety, is of darker color, more compact texture, drier, though not so brittle, with a stronger and more disagreeable taste, being intensely bitter and nauseous, with little or nothing of the aromatic flavor of the Socotrine; it is extremely apt to induce hemorrhoids, and is principally used among veterinary physicians.

ALOE SOCOTRINA (U. S. P.), Socotrine aloes. "In hard masses, occasionally soft in the interior, opaque, yellowish-brown, orange-brown or dark ruby-red, not greenish, translucent on the edges; fracture resinous, somewhat conchoidal. When breathed upon, it emits a fragrant, saffron-like odor. Taste peculiar, strongly bitter. Almost entirely soluble in alcohol and in 4 parts of boiling water. The aqueous solution becomes turbid on cooling and yields a deposit. Mixed with alcohol and examined under the microscope, Socotrine aloes exhibits numerous crystals. The powder, on being thoroughly dried on a water-bath and then heated to 100° C. (212° F.), should not cake. Mixed with nitric acid, it acquires a reddish-brown color. Socotrine aloes is not colored blue on being mixed with sulphuric acid and blowing the vapor of nitric acid over the mixture (difference from Natal aloes)"—(U. S. P.). It is hard and friable in the winter, somewhat plastic in summer, and growing soft between the fingers; easily pulverizable; and, when reduced to powder, of a bright, golden color. Aloes of superior value, whether from the Island of Socotra or not, are often commercially designated as Socotrine aloes—(Ed., Duncan).

ALOE CAPENSIS, Cape aloes (Shining aloes). Cape aloes has a glossy or resinous fracture, a deep-brown or olive color, with a greenish tint, a shining, smooth surface; and thin scales of it are nearly transparent, having a ruby color. Its odor is more powerful and unpleasant than the Barbadoes aloes; its taste peculiar and bitter; and its powder is bright yellow, somewhat like gamboge, but having a greenish tint. The finer East Indian varieties are sometimes confounded with the Socotrine.

OTHER ALOES.—Hepatic aloes is the name applied to a variety of Socotrine aloes at one time commercial in Europe. In this country Barbadoes aloes has been called by this name. Any of the opaque and liver-colored aloes have also been known under this term. Jefferabad aloes (already referred to) is inferior in taste and odor to the Socotrine and has a lustrous, pitch-black color. Natal aloes, from Natal, is of a pale brown-yellow or a brown-gray color, quite different from the other varieties. It is carefully prepared, but the plant yielding it is still undetermined. Moka aloes, is a disagreeably odorous, nearly black, opaque variety, prepared in Arabia. Caballine aloes (Horse aloes) was the term by which impure and fetid grades of various sources were formerly known in European commerce.

Aloe Purificata (U. S. P.), PURIFIED ALOES.—The following is the Pharmacopoeial method for purifying aloes, and a description of the product: Take "Socotrine aloes, one thousand grammes (1000 Gm.) [2 lbs. av., 3 ozs., 120 grs.]; alcohol, two hundred cubic centimeters (200 Cc.) [6fl℥, 366♏︎]. Heat the aloes by means of a water-bath until it is completely melted. Then add the alcohol, and having stirred the mixture thoroughly, strain it through a No. 60 sieve, which has just been dipped into boiling water. Evaporate the strained mixture by means of a water-bath, constantly stirring, until a thread of the mass becomes brittle on cooling. Lastly, break the product when cold into pieces of a convenient size, and keep it in well-stoppered bottles. The product is in irregular, brittle pieces of a dull-brown or reddish-brown color, and having the peculiar, aromatic odor of Socotrine aloes. It is almost entirely soluble in alcohol"—(U. S. P.). Aloe should never be boiled for any length of time, as its medicinal virtues are thereby diminished. It is dissolved by alcohol, whether diluted or not. A clear solution made with cold water reddens litmus, gives a deep, olive-brown color with ferric chloride, is deepened in color by alkalies, is unchanged with gelatin, and forms a copious yellow precipitate with acetate of lead. Heat occasions fusing, frothing, charring, and ignition, burning with a crackling noise, and a dense smoke which has the peculiar aloetic smell.

Chemical Composition.—The disagreeable odor and taste of aloes is due to a pale yellow, mobile, volatile oil, but minute traces of it existing in the plant. Aloes contains a resin, Resin of aloes, being that portion which separates upon cooling the hot aqueous solution of the drug. The chief body of interest, however, is that announced by T. & H. Smith, of Edinburg, and called aloin. As it was first found in Barbadoes aloes, it is now known as barbaloin, since a similar but distinctly different substance was later found in Socotrine Aloes, called socaloin, and in the Natal variety, nataloin, all three being closely connected chemically but having each distinctive differences. The aloëtin (aloësin, resino-amara [of Braconnot], or aloe bitter), the bitter extractive of aloes of Robiquet and other early investigators, was probably aloin in an impure, or at least modified, condition. The official aloin is composed of barbaloin or socaloin (see Aloinum).

Barbaloin (C17H20O7, Sommaruga and Egger, 1874), forms small yellow crystals, soluble in water, alcohol and ether (see Aloinum). Brilliant yellow needles of bromaloin may be produced with it by treating its cold, aqueous solution with bromine water, and recrystallizing from alcohol; chloraloin may likewise be produced from it. A rapidly-fading crimson color is struck when treated to a drop of nitric acid. Heated with the same acid, it yields aloetic, chrysammic, picric and oxalic acids (Tilden).

Socaloin (C15H16O7, Sommaruga and Egger), was observed by Pareira (1852) in the liquid Socotrine aloes, brought into England and isolated, in 1856, by T. B. Groves, who regarded it as identical with the preceding. Histed (1871) proved it to be distinct. It forms in small, tufted, yellow needle-crystals, soluble in absolute alcohol, water, ether, acetic ether, and methyl alcohol (see Aloinum). Heated with nitric acid an orange-red coloration ensues, and acids corresponding with those obtained from barbaloin are obtained. This form is also known as zanaloin. Tilden, in 1886, obtained from both kinds of aloin yellow crystals of alorxanthin (methyl-tetraoxyanthraquinone) by oxidation with potassium chromate and sulphuric acid.

Nataloin (C16H18O7, Sommaruga and Egger) was first isolated by Prof. Flückiger, in 1871, from Natal aloes. It forms thin, light-yellow scales, soluble, according to Flückiger, at 15.5° C. (60° F.), in methylic alcohol (1 in 35), acetic ether (1 in 50), ether (1 in 1236), and in absolute alcohol (1 in 230). Water, hot or cold, very sparingly dissolves it. It is soluble in alcohol (60 parts). Picric and oxalic acids, but not chrysammic acid, are formed from it by treatment with nitric acid. This variety does not yield a bromine compound.

If the formulae above given for the three varieties of aloin by E. von Sommaruga and Egger, of Vienna (1874), be correct, these bodies would seem to constitute an homologous series.

The following beautiful tests for the three aloins were pointed out by Histed: "A drop of nitric acid on a porcelain slab gives, with a few particles of barbaloin or nataloin, a vivid crimson, but produces little effect with socaloin. To distinguish barbaloin from nataloin, test each by adding a minute quantity to a drop or two of oil of vitriol, then allowing the vapour from a rod touched with nitric acid to pass over the surface. Barbaloin (and socaloin) will undergo no change, but nataloin will assume a fine blue"—(Pharmacographia).

The afore-mentioned aloetic acid has the composition C7H2(NO2)2O, and is orange-red, while chrysammic acid (C14H4[NO2]4[OH]2O), occurs in laminae of a vivid golden-yellow color. It has an explosive property when heated. Needles of an indigo color of the sublimable body hydrochrysamide, are produced from the last-named acid by means of deoxidizers. The resin of aloes was found by Tilden and Rammell, in 1872, to be separable into two resins—one soluble by prolonged boiling; the other insoluble. While both are nearly similar to barbaloin in composition, the first lacks the elements of water, being regarded as the anhydrid of barbaloin. The insoluble resin is very similar in structure.

Czumpelik (1861), by prolonged boiling of Socotrine aloes with an alkali, and Hlasiwetz (1865) with sulphuric acid, obtained para-cumaric acid (C6H4[OH].CH:CH.COOH.). This, when fused with potassium hydroxide, yields para-oxybenzoic acid. Alorcinic acid was also obtained with these bodies by Weselsky (1872). By distillation of aloes with quick-lime, Robiquet (1846) obtained a yellowish oil, aloïsol, an odorous body since shown by Rembold to be a mixture of xylenol (dimethylated phenol), acetone, and hydrocarbons. Aloes, distilled with zinc-dust, yielded Graebe and Liebermann (1868) anthracene (C14H10), and Liebelt, in E. Schmidt's laboratory, methylanthracene.

Action, Medical Uses, and Dosage.—Tonic, purgative, emmenagogue, and anthelmintic. In doses of from ½ grain to 1 grain, 2 or 3 times a day, aloes exerts a decided tonic influence, but is seldom resorted to for this purpose. As a laxative and purgative, its applications are unbounded; it acts more especially on the muscular coat of the large intestines, rather increasing their peristaltic motion than effecting copious, thin or watery discharges; and from its tendency to produce heat and irritation about the anus, it is extremely improper (except in minute doses in debilitated individuals) for persons disposed to or troubled with piles. When applied endermically to an ulcer or blistered surface, it purges as effectually and promptly as when taken into the stomach; 10 grains used thus will purge in from 6 to 10 hours. Administered to nursing mothers it will purge the sucking child. It is commonly supposed to have no action on the jejunum or ileum; and some imagine it to influence the duodenum, especially the mouths of the biliary ducts, causing an increased flow of bile and stimulating the intestinal canal, when that secretion is suspended, as in jaundice. It acts upon the uterus, promoting the menstrual flow, which is partly owing to the stimulation of the organ, and the determination of blood toward it, occasioned by the medicine. It is said that 1 to 3 grains of extract of hyoscyamus, or hops, or 2 grains of ipecacuanha, mixed with the aloetic dose, will prevent its irritating effect on the lower intestines. An increase of the quantity of aloes beyond the medium dose is not attended by a corresponding increase of effect. Aloes has been efficacious in constipation, dyspepsia, and ascarides; in this last instance being used in form of an injection, 10 grains to 3 ounces of water, for children. In chlorosis and amenorrhoea, it has often proved serviceable, and is used for this purpose in various combinations. In cases of delicate females, with loss of appetite, torpor of the bowels, and suffering, with suppression of the menses, the following has been recommended for the purpose of exciting proper ovarian or uterine action: Take of the best aloes, pulverized, asafoetida, pulverized, each, ½ drachm; cantharides, pulverized, 20 grains; mix and rub well together with a little soap, and divide into 20 pills. Of these give from 1 to 3, 3 times a day. If the patient be very feeble, some of the salts of iron may also be added. Injections of aloes, composed of from 10 to 30 grains dissolved in 2 or 3 fluid ounces of water, and thrown up the rectum daily, and continued for a week previous to the menstrual period, have sometimes proved effectual. For habitual constipation, aloes should never be given in cathartic doses. Debility and marked intestinal torpor point to its selection. Rx Aloes, gr. j; powdered ipecac, gr. ss; extract nux vom., gr. ¼. Mix. Make 1 pill. Sig.: Give 1 such pill from 1 to 3 times a day, according to the condition. If the liver is active, less of aloes will be required than if it be torpid. A pill of aloin, belladonna, ipecac and strychnine, is much used in chronic constipation. There are some cases of piles, with marked relaxation of the rectal tissues, that are benefited by minute doses of aloes or aloin, and both are effectual remedies in rectal prolapse, due to debility. In both cases there is an associated condition of feeble innervation, in which case the minute dose tends to increase the nutrition of the nervous system.

Aloes should never be given in inflammatory affections, in irritable, plethoric habits, in gastritis, enteritis, and, as a rule, where piles are present; nor to females liable to sudden uterine evacuations, nor during pregnancy. In hemorrhoids it may be given when modified by combination, or in the minute doses above referred to. Soap, or an alkaline carbonate, lessens its irritant action. The union of other purgatives with aloes often modifies its tendency to irritate the rectum. One grain of aloes with 2 or 3 grains of sulphate of iron will also modify this action, and will produce as much effect as 2 or 3 grains of aloes. As a laxative, aloes will be found useful in habitual constipation, from intestinal torpor, jaundice, scrofula, hypochondriasis; and as a cathartic, where there is a tendency to cerebral congestion. Dose of aloes is from ¼ to 10, or even 20, grains; and the most convenient form of administration is that of pill. It enters as a constituent into a great number of useful compound remedies.

Specific Indications and Uses.—"Atony of large intestine and rectum, mucoid discharges, prolapsus ani, pruritis ani, ascaris vermicularis" (Scudder, Dis. of Children, 1882). Difficulty in evacuating the lower bowel.

King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.