Guaiaci Resina (U. S. P.)—Guaiac.
Related entry: Guaiaci Lignum (U. S. P.)—Guaiacum Wood
The resin of the wood of Guaiacum officinale, Linné"—(U. S. P.).
SYNONYMS: Guaiacum, Guaiacum resin, Resina guajaci.
Source and Preparation.—The resin of guaiacum, or gum guaiacum as it is erroneously called by some, is procured from the wood of the tree, by natural exudation; by jagging or wounding the tree in several places; by heat applied to the wood sawed into large billets; and by boiling the chips of the wood in water and salt, and skimming off the resin as it floats on the surface (Ed.—P.). The last two modes are the most frequent in use.
Description and Tests.—Guaiacum is ordinarily met with in amorphous, hard masses of varying sizes, in which are found pieces of wood, dirt, and other foreign matters. It has a sweetish, faintly bitter taste, succeeded by a lasting acrimony, especially in the fauces. It does not soften by the heat of the hand, becomes tough when chewed, and is fusible at a moderate heat. Its specific gravity is 1.20 to 1.23. It is readily reduced to powder, becoming somewhat tenacious, and quickly aggregating, by the action of the air. Guaiac resin is officially required to be in "irregular masses, or subglobular pieces, externally greenish-brown, internally of a glassy lustre, and, in recent guaiac, usually reddish-brown, transparent in thin splinters, fusible, feebly aromatic, the odor becoming stronger on heating; taste somewhat acrid; powder grayish, turning green on exposure to air. Soluble in potassium or sodium hydrate T.S. and in alcohol; the alcoholic solution is colored blue on the addition of tincture of ferric chloride"—(U. S. R).
The resin is practically insoluble in water, soluble, although not completely, in ether and oil of turpentine, easily soluble in acetone, amyl alcohol, chloroform and in creosote: fixed and volatile oils scarcely dissolve it, although oil of cloves and cassia oil are capable of dissolving appreciable quantities. Benzin, benzol and carbon disulphide dissolve the resin very sparingly. Guaiac resin is remarkable for the blue color reaction it yields in alcoholic solution (1 in 100) with ozonizers (Schönbein's ozonide). Ozone, chlorine, bromine and iodine, nitrous acid, chromic acid, hypochlorites, ferric salts, lead and manganese dioxide, etc., and some organic substances, especially vegetable ferments and enzymes of the most obscure kind, e.g., the enzymes existing on freshly cut raw potato, etc., (oxidation ferments of Schönbein), cause a rapid bluing of tincture of guaiac. According to Prof. Ed. Schaer (Forschungsberichte über Lebensmittel, Vol. III, 1896, p. 1), the blue color is due to a very unstable ozone compound of guaiaconic acid (see Chemical Composition). Its formation is prevented by light, heat, free acids, especially by alkalies, but acetic acid, even in the form of glacial acetic acid, singularly promotes its formation. In contrast with these ozonizers stand Schönbein's antozonide (antozonizers), substances otherwise capable of giving off oxygen, but incapable of reacting with tincture of guaiac. The type of these substances is hydrogen peroxide (H2O2). They become active, however, toward tincture of guaiac through the intervention of certain inorganic substances, and a number of fluids containing animal and vegetable ferments, e. g., malt extract, saliva, fresh milk, or the red corpuscles of the blood. Schönbein, the discoverer of ozone, was the first to base upon this behavior the well-known guaiac test for blood, often believed to be fallacious, while Prof. Schaer pronounces it exceedingly characteristic and sensitive if properly carried out.
Prof. Schaer, in the paper mentioned, publishes a new mode of carrying out this test, to which be has given 30 years' time of successful trial. This test is based on the following observation: When an alcoholic tincture of guaiac is poured into an aqueous solution of blood acidified with acetic acid, the guaiac resins, in precipitating, carry along with them almost quantitatively the blood coloring matter present in the fluid. Filter through paper and dry the latter with its contents, taking especial care to exclude light and air as much as possible. The blood test is then produced by moistening small pieces of the filtering paper with water and adding hydrogen peroxide solution containing some acetic acid. If blood is present the paper and liquid assume a pure blue color. The test can be applied with equal success to dry blood stains, and after a period of 5 or even 10 years after drying the paper. A modification of this process, involving the use of a concentrated aqueous solution of chloral hydrate to dissolve dried blood stains, is carried out as follows: Moisten the blood stains with acetic acid, extract with a 70 per cent solution of chloral hydrate, add an equal volume of guaiac-chloral solution (1 per cent guaiac resin in 70-75 per cent chloral hydrate); if ammonium nitrate is absent, a yellow-brown mixture results (otherwise a blue coloration takes place at once). If now the mixture is superposed by Hünefeld's solution (15 Cc. of a 3 to 5 per cent solution of hydrogen peroxide, 25 Cc. of alcohol, 5 Cc. of chloroform, and 1.5 Cc. of glacial acetic acid), previously ascertained not to react with a mixture of chloral and guaiac, an intensely blue zone is developed at the surface of contact of both fluids if blood is present. Soluble ferrous salts mixed with the blood stain also give the reaction (Archiv der Pharm., 1898, p. 574).
Reversely, this reaction with ozonizers can be used as a delicate test for the presence of the resin of guaiacum in other resins, e. g., scammony, jalap, etc. Guaiac is subject to adulteration with pine resin and other substances. This may be detected by observing that the genuine article, when heated, does not exhale a turpentine odor, and that oil of turpentine dissolves resin but not guaiac. Sulphuric acid forms with guaiac a deep-red solution; nitric acid dissolves it without the aid of heat, and with strong effervescence yielding oxalic acid upon evaporation. The so-called Peruvian guaiac resin, analyzed by E. Kopp (Archiv der Pharm.,  Vol. IX, p. 193), is entirely different from guaiac resin, and therefore does not give the characteristic reaction for this resin.
Chemical Composition.—In 1862, Hadelich found the composition of guaiac resin to be as follows: "Guaiaconic acid, 70.3 per cent; guaiac-resinic acid, 10.5 per cent; guaiac-beta-resin, 9.8 per cent; guaiacic acid, guaiac-yellow and impurities, 4.9 per cent; gum, 3.7 per cent; ash constituents, 0.8 per cent "(Flückiger, Pharmacognosie, 1891). The first three substances may be differentiated from the guaiac resin as follows: To a concentrated alcoholic solution of the resin (1 part) add a warm alcoholic solution of potassium hydrate (½ part), and allow the mixture to stand for 24 hours; a magma of crystals results, consisting of the potassium salt of guaiac-resinic acid. Strain through cloth, evaporate the mother liquor to a syrup, add absolute alcohol in order to remove some more of this potassium salt. Now charge the alcoholic solution with carbonic acid gas, which precipitates the potassium as carbonate, filter, add water, acidulate with hydrochloric acid and distill off the alcohol. The residual resin is then washed with warm water and treated with ether. Guaiaconic acid is thereby dissolved, while guaiac-beta-resin remains. The substances thus obtained are then purified by further treatment, for which see details in Husemann and Hilger, Pflanzenstoffe, p. 857.
Guaiaconic acid (C19H20O5., isolated by Hadelich, in 1862, is the chief constituent of guaiac resin (70 per cent), and is the substance to which is due the blue color reaction with oxidizing agents. Prof. Schaer (Wittstein's Vierteljahrsschrift, 1873, p. 68), however, remarks that guaiaconic acid, when exposed to direct sunlight loses its property of turning blue with oxidizers, even when the air is excluded. It is a tasteless and odorless, brownish, amorphous body, fusible near the boiling point of water, easily soluble in alcohol, ether, chloroform, acetic ether and acetic acid. It is optically laevo-rotatory, forms soluble amorphous salts with alkalies, decomposable by the carbonic acid of the air, and forms insoluble salts with heavy metals. It dissolves in concentrated sulphuric acid with a cherry-red color, water precipitating violet flakes from this solution. Dry distillation yields an oily distillate.
Guaiac-resinic acid (C20H26O4) was discovered by Hlasiwetz, in 1859, and is a crystallizable substance, insoluble in water, soluble in alcohol, ether, chloroform, benzol, carbon disulphide, acetic ether and acetic acid, also in solution of caustic soda or potash, but not ammonia. It melts between 75° and 80° C. (167° and 176° F.). It dissolves in sulphuric acid with a cherry-red color. Water precipitates white flakes from this solution. When heated with hydrochloric acid this substance (as well as guaiaconic acid) yields methyl chloride and pyrocatechin (C6H4[OH]2). Fused with caustic potash, it yields protocatechuic acid (C6H3[OH]2.COOH) (Hlasiwetz and Barth). Upon dry distillation it yields guaiacol (C6H4OCH3[OH]) (which see) (Guaiacol: not scanned; definition: "Guaiacol is obtained from beechwood creosote (see Creosotum) ... ") (Creosotum: not scanned; definition: "A mixture of phenols ... obtained during the distillation of wood-tar ..."), and crystallizable pyroguaiacin. The yield of this substance is 0.5 per cent. It melts at 180° C. (356° F.), is soluble in alcohol and ether, insoluble in water, can be sublimed in the form of needles or scales, which turn green with ferric chloride, and blue with warm sulphuric acid. When heated with zinc dust, the hydrocarbon guaien (C12H12) is obtained, forming fluorescing plates.
Guaiacic acid (C6H8O3, Deville) was first obtained, in 1837, by Righini from guaiac wood as a white crystallizable substance. In 1841, Thierry isolated it from both the wood and the resin. It forms white needles, resembling benzoic acid, but is more soluble in water than the latter; also soluble in alcohol and in ether. Only 0.005 per cent of this acid could be obtained by Hadelich from guaiac resin. Deville found this substance upon rapid sublimation to decompose into carbonic acid and guajacen (guajol) (C5H8O), a colorless oil, of the odor of bitter almonds. It was found by Lieben and Zeisel (confirmed by Herzog, Berichte, 1882, p. 1085) to be identical with tiglin-aldehyde (CH3CH:C[CH3].CHO), convertible by oxidation into tiglic acid, a constituent of Roman chamomile oil, as well as of croton oil,
Guaiac yellow was first observed by Pelletier, and obtained by Hadelich (1862) in yellowish quadratic plates of neutral reaction and bitter taste, not easily soluble in water, diluted acids and chloroform, soluble in alcohol, ether, carbon disulphide and alkalies, in the latter with yellow color. With concentrated sulphuric acid it forms a beautiful blue solution, turning green, then yellow.
The resin of guaiac, upon dry distillation, yields a brown-red tar containing guaiacol (C7H8O2) (see Guaiacolum) (not included in this scanned version), pyroguaiacin (C12H10OH.OC6H6[OH]), guaiol (guaiacen, tiglin-aldehyde, C5H8O), and kreosol (C8H10O2). Fusion with caustic potash yields protocatechuic acid, and by distillation with zinc dust, K. Bötsch (Amer. Jour. Pharm., 1881, p. 60) obtained 50 per cent kreosol, 30 per cent toluol, meta and paraxylol, pseudocumol, and the hydrocarbon guajon or guaien (C12H12), aforenamed, which is identical with the guaiacen prepared by Wiesner.
Action, Medical Uses, and Dosage.—(See Guaiaci Ligni also.) Guaiac is stimulant. Taken internally it produces the same effects as named in the wood, but in a more active degree. Large doses act as a cathartic. It is used in the same affections as guaiaci ligni or guaiacum wood. Several practitioners have found it beneficial in amenorrhoea, dysmenorrhoea, and other uterine diseases, all of atonic character, likewise in acute dysentery, in which its employment is said to be followed by speedy beneficial results. It is much used in chronic rheumatism, and in the abating stages of the acute form, and has proved a most valuable agent in these diseases. It is said to be an antidote to the effects of the tincture of Rhus Toxicodendron. If the preparations of guaiacum produce sickness, defective appetite, and irregularity of the bowels, their use must be discontinued. Guaiac gained its greatest reputation in the treatment of constitutional syphilis, having been liberally used for centuries in the treatment of that malady, but at the present day it is almost discarded as an antisyphilitic. It undoubtedly benefits some cases of rheumatism and is well endorsed as a remedy for rheumatic sore throat or rheumatic pharyngitis. A tincture of guaiac, or preferably the ammoniated tincture is to be used. The latter preparation, as well as troches of the powder, have been highly endorsed as a remedy to abort tonsilitis. For this purpose they must be given early or good effects fail to be produced. In chronic rheumatism, where the circulation of the blood is feeble and the vital functions greatly depressed, and the hands and feet are cold, from 30 to 60 drops of the tincture may be used with expectation of benefit. A good tincture is prepared by macerating 8 ounces of guaiac in 1 pint of alcohol. Guaiac is also of some value in atonic dyspepsia, provided no inflammation is present. Certain chronic skin diseases, requiring stimulation, are benefited by guaiac. From 1/20 to 1/10 grain of the resin in ½ ounce of thick malt extract is recommended as a remedy for habitual constipation. Guaiac is a remedy in atonic conditions only. It is contraindicated in all active febrile, plethoric, or inflammatory conditions, or where there is vascular excitement, tending to hemorrhage, or impaired digestion, with tendency to irritation (Locke). Dose of the powdered resin, from 5 to 20 grains; of the tincture, from 1 to 4 fluid drachms, either of which may be repeated 3 or 4 times a day; ammoniated tincture of guaiac, 10 drops to 1 fluid drachm. A mixture of 10 grains each of guaiac and compound powder of ipecacuanha and opium has been found of advantage in rheumatism and dysentery.
Specific Indications and Uses.—Dryness and stiffness of the throat, with tumid, swollen tonsils, painful deglutition, and dribbling of saliva; incipient tonsilitis (if used early); rheumatic pharyngitis.