BENZOINUM. U. S., Br.; Benzoin; Sumatra Benzoin; Styrax;

Benzoin comes as a gum or resin and is quite hard

BENZOINUM. U. S., Br.; Benzoin; Sumatra Benzoin; Styrax;
"Benzoin is the balsamic resin obtained from Styrax Benzoin Dryander, known in commerce as Sumatra Benzoin, or from Styrax tonkinensis (Pierre) Craib ex Hartwich, or other species of Styrax, known in commerce as Siam Benzoin (Fam. Styracece), Sumatra Benzoin yields not less than 75 per cent of alcohol-soluble extrac-tive. It yields not more than 1 per cent of acid-insoluble ash. Siam Benzoin yields not less than 90 per cent of alcohol-soluble extractive. It con-tains not more than 1 per cent of foreign organic matter and yields not more than 0.5 per cent of acid-insoluble ash.

The Br. limits the source of benzoin to Styrax Benzoin and specifies a purity rubric of 19 to 29 per cent of free balsamic acids and 30 to 60 per cent of total balsamic acids, based on the dry, alcohol-soluble matter.

Various other names: Gum Benjamin. Benzoe; Resina Benzoe; Asa Odorata; Asa Dulcis. Fr. Benzoin du Laos, dit de Siam. Ger. Benzoe; Benzoeharz; Siam-benzoe; Benzoino; Bel-gioino. Sp. Benjui.

Sumatra Benzoin is obtained from Styrax Benzoin Dryander and possibly from S. sumatranus J. J. Smith.

Styrax Benzoin, or Benjamin Tree, is a tall tree of quick growth, sending off many strong round branches, covered with a whitish downy bark. Its leaves are alternate, entire, oblong, pointed, smooth above and stellate-tomentose beneath. The flowers are in compound, axillary clusters, nearly as long as the leaves, and usu-ally hang, all on the same side, upon short slender pedicels. The tree is a native of Sumatra, Java, Borneo, and other islands in the vicinity. Strueff presents a careful morphological paper on the trees of Styrax Benzoin, growing in Siam, Su-matra and Java, in A. Pharm., 1911, 249, 10. F. Reinitzer gives an elaborate account of the col-lection of Sumatra Benzoin at Palembang (see A. Pharm., 1926, 264, 368). The exudation is purely the result of pathological processes, the plant containing no resin receptacles. The trees, which are either wild or cultivated, are deemed of a proper age to be wounded at six years, when the trunks are usually about seven or eight inches in diameter. Once a year the bark is wounded near the origin of the lower branches; the sap which exudes hardens on exposure to the air. The product on each occasion from one tree never exceeds three pounds. The juice which first flows is the purest, and affords the whitest and most fragrant benzoin.

The tree or trees yielding Siam Benzoin have long been a source of controversy. According to E. M. Holmes one of them possesses leaves thinner and less distinctly venated than those of the Styrax Benzoin. Hartwich believed it to be a new species, Styrax benzoides Craib (see Kew Bulletin, 1912, p. 391). Holmes (P. /., 1916, 804) attributed it, however, to the S. tonkinensis. Rordorf (P. J., 1917, 99, 111) received some fruits which were sent him from Bangkok as specimens supposedly derived from the Benzoin tree; these did not agree with any species previously described and he proposed a new species, S. siamensis Rordorf. It seems probable that one or more members of the sec-tion Anthostyrax Pierre of the genus Styrax in-cluding S. tonkinensis (Pierre) Craib ex Hartwich yield the Siam variety. The territory from which the balsam is derived is a quite limited district in the Siamese Province of Luang Pro-bang along the River Mekong.

The Siam Benzoin appears in commerce as two sub-varieties either in the form of separate tears {Tear Siam benzoin) or in masses com-posed of tears cemented together by a rich amber-colored translucent resin, these masses usually being in cubical blocks which take their form from the wooden boxes in which the soft resin has been packed (Block Siam benzoin). The tears are small, mostly less than 2 or 3 cm. in length, opaque, brittle and milky white on the interior, but on keeping gradually oxidize into the reddish-brown, transparent or translucent resin. The finest variety is composed almost entirely of these tears, loosely agglutinated to-gether. Sumatra Benzoin is sent into commerce chiefly from Palembang in Sumatra. It differs from the Siam varieties in having a much grayer color; the resin is grayish-brown, the tears are usually fewer than in the finer variety, and the bits of wood, etc., more abundant. The odor differs from, and is less agreeable than, that of Siam Benzoin. "Palembang Benzoin" is an in-ferior variety of Sumatra Benzoin, of lighter weight and having an irregular, porous fracture. It is the poorest of four grades of benzoin pro-duced at Palembang, Sumatra. It consists of a reddish-brown resinous substance with only a few tears imbedded in it. It is claimed to yield a larger percentage of benzoic acid and is used as a source of that product. It is also asserted that it can be distinguished by its tincture, when dropped into water, not producing milkiness, but a flocculent deposit. Penang Benzoin also re-sembles Sumatra Benzoin, but has an odor which is more like that of storax, and it is probably yielded by the Styrax Benzoin; possibly it is the product of one of the Sumatran species, S. sub-denticulata Mig. For an account of the cultiva-tion and collection of benzoin in Sumatra see Reinitzer (A. Pharm., 1926, 264, 368).

A variety of benzoin known as Estoraque or Benjui, is produced in Bolivia from the Styrax Pearcei Perk. var-. bolivianus. This has been shown by Wichmann (5. W. P., 1912, p. 237) to be of similar composition to the Asiatic resin. According to this author resins are also collected from a number of other species of Styrax in South America.

During 1939, 135,161 Ibs. of benzoin were imported into this country from the Nether-lands Indies, French Indo-China, Thailand, France and London.

Description and Tests.—"Unground Sumatra Benzoin.—Blocks or lumps of varying size, made up of tears, compacted together with a reddish brown, reddish gray, or grayish brown resinous mass; tears externally yellowish or rusty brown, milky white on fesh fracture; hard and brittle at ordinary temperatures, but softened by heat and becoming gritty on chewing; odor aromatic. When digested with boiling water, the odor sug-gests cinnamates or storax; taste aromatic and slightly acrid.

"Unground Siam Benzoin.—Pebble-like tears of variable size, compressed, yellowish brown to rusty brown externally, milky white on fracture, separate or very slightly agglutinated, hard and brittle at ordinary temperatures but softened by heat and becoming plastic on chewing; odor agreeable, balsamic; vanilla-like; taste aromatic and slightly acrid.

"Identification.—The solution of Benzoin in alcohol becomes milky upon the addition of water and is acid to litmus paper. Heat a few frag-ments of Benzoin in a test tube: Sumatra Ben-zoin evolves a sublimate consisting of plates and small, rod-like crystals that strongly polarize light. Siam Benzoin evolves a sublimate directly above the melted mass consisting of numerous long, rod-shaped crystals, which do not strongly polarize light. Treat about 0.25 Gm. of Benzoin with 5 cc. of ether, decant about 1 cc. of the ether solution into a porcelain dish, and add to it 2 or 3 drops of sulfuric acid: the solution of Sumatra Benzoin produces a deep reddish brown coloration of the sulfuric acid and the solution of Siam Benzoin produces a deep purplish red coloration. Cinnamic acid.—Heat about 0.5 Gm. of Benzoin in a test tube with 10 cc. of potassium permanganate T.S.: only the Sumatra variety develops a strong odor of benzaldehyde. Benzoic acid.—Treat about 1 Gm. of powdered Benzoin with 15 cc. of warm carbon disulfide, filter, wash the filter with an additional 5 cc. of carbon di-sulfide, and allow the filtrate to evaporate spon-taneously: the weight of the residue is not less than 12.5 per cent of the weight of the Benzoin taken. This residue responds to the test for identification under Acidum Benzoicwn." U. S.

The Br. identity tests include the sublimation test and the production of benzaldehyde by oxida-tion with potassium permanganate. Under purity tests an acid value of 115 to 163, an ester value of 47 to 83, and a saponification value of 169 to 223, all referred to the dry alcohol-soluble matter, are required. Not more than 2 per cent of ash is permitted and upon continuous extract tion with 90 per cent alcohol not more than 20 per cent of insoluble residue, dried at 100° C., is allowed. Upon drying the coarsely powdered material in vacua over sulfuric acid the loss in weight should not be more than 10 per cent.

Benzoin has a fragrant odor, with very little taste, but when chewed for some time leaves a sense of irritation in the mouth and fauces. It breaks with a resinous fracture, and presents a mottled surface of white and brown or reddish-brown ; the white spots being smooth and shining, while the remainder, though sometimes shining and even translucent, is usually more or less rough and porous, and often exhibits impurities. After long storage it becomes covered with a thin yellow transparent film which Reinitzer finds is due to oxidation of the proper resin (Schim. Rep., April, 1915). In the inferior kinds the white spots are very few, or entirely wanting. Benzoin is easily pulverized, and, in the process of being powdered, is apt to excite sneezing. Its sp. gr. is from 1.063 to 1.092. When heated it melts, and emits thick, white, pungent fumes, which excite coughing when inhaled, and consist chiefly of benzoic acid. It is wholly soluble, with the exception of impurities, in alcohol, and is precipitated by water from the solution, ren-dering the liquid milky. It yields to boiling water a notable proportion of benzoic acid. Lime water and the alkaline solutions partially dissolve it, forming benzoates, from which the acid may be precipitated by the addition of other acids.

Assay.—"Place about 2 Gm. of Benzoin, ac-curately weighed, in a tared extraction thimble, and insert the thimble in a Soxhlet or other suit-able continuous extraction apparatus. Place about 0.1 Gm. of sodium hydroxide in the re-ceiving flask of the apparatus, and extract the Benzoin with alcohol for 5 hours, or until com-pletely extracted. Dry the insoluble residue at 100° C. for 4 hours, and weigh. Determine the amount of moisture in the drug by the Toluene Method—IX. Calculate the weight of moisture in the quantity of the Benzoin used for the assay, and subtract it from the original weight of the Benzoin taken for the assay. The difference be-tween this result and the weight of the residue determined above represents the alcohol-soluble extractive." U. S.

The Br. assay for total balsamic acids is car-ried out by boiling about 2.5 grams, accurately weighed, with 25 cc. of N/2 alcoholic potassium hydroxide under a reflux condenser for an hour; then evaporating the alcohol and digesting the residue with 50 cc. of hot water until a uniform diffusion is produced. The liquid is cooled, 150 cc. of water and a solution of 2.5 grams of magnesium sulfate in 50 cc. of water added and after thorough mixing the flask and contents are set aside for ten minutes. The liquid is then filtered by suction and the residue washed with 20 cc. of water. After acidification, the filtrate and washings are shaken successively with 50, 40, 30 and 30 cc. portions of ether. The mixed ethereal solutions are in turn shaken with 20, 20, 10, 10 and 10 cc. portions of a 5 per cent (weight in volume) solution of sodium bicarbonate and each portion in turn washed with 20 cc. of ether, the same ether being used to wash each portion of the aqueous sodium bicarbonate solution. The ethereal liquids are rejected; the mixed aqueous solutions are acidified with hydrochloric acid and then shaken with successive 30, 20, 10, and 10 cc. portions of ether. The ether is volatilized and the residue, after distribution over the surface of the flask, is dried in a vacuum desiccator over sulfuric acid and finally weighed as bal-samic acids.

To determine free balsamic acids the alcohol-soluble extractive from 2.5 grams of benzoin is dissolved in 15 cc. of hot, 90 per cent alcohol, and to this is added a mixture of 10 cc. of a 5 per cent (weight in volume) solution of potas-sium hydroxide and 50 cc. of water. After mix-ing, 150 cc. of water and a solution of 2.5 grams of magnesium sulfate in 50 cc. of water are added and the flask and contents placed on a boiling water-bath for five minutes. After cool-ing the mixture is filtered by suction and the determination completed as described under the determination of total balsamic acids.

The percentage of alcohol-soluble matter re-quired to be present by the U. S. P. in benzoin is high enough to exclude Sumatra Benzoin in all but its very finest varieties. Pursel and Graham obtained from five commercial varieties of Su-matra Benzoin, in the American market, an average of 86 per cent of soluble matter. (Proc. Pennsylvania Pharm. Assoc., 1902.) Barclay, in England, found the average of ten samples to be 69.9 per cent. (P. J., Jan., 1903.)

Benzoin retards the oxidation of fatty matters, and thus tends to prevent rancidity.

Constituents.—Our knowledge of the constitu-tion of Siam Benzoin has been greatly advanced by the elaborate investigations of Reinitzer (A Pharm., 1926, 264, 131). He has shown that the fresh exudate is composed chiefly of: crystal-line coniferyl benzoate (lubanyl benzoate} about 78 per cent, with a little less than 12 per cent of benzoic acid, and 6 per cent of an organic acid siaresinolic (benzoresinol); these bodies, all of which are solids, are liquefied by the presence of a little more than 2 per cent of cinnamyl benzoate and traces of vanillin. As the resin hardens there is an evaporation of most of the cinnamyl benzoate and a change in a portion of the coniferyl benzoate from a crystalline to an amorphous condition. Coniferol has the chem-ical formula of CeHsOH.OCHs.CsI^OH; its ben-zoate occurs in crystalline masses with a melting point of 72° C.

The proportion of free benzoic acid is difficult to determine accurately because of the ease with which coniferyl benzoate is saponified by alkalies.

The composition of Sumatra Benzoin is not so well understood, but apparently cinnamic acid replaces much of the benzoic acid present in the Siam variety, and sumaresinol replaces the siaresinol. In it are also traces of styracin (cinnamyl cinnamate), styrene (phenyl ethylene, see under Synthetic Rubber, Part II), benzalde-hyde, and vanillin (see Brans, Pharm. Weekbl, 1936, 73, 374).

According to Cocking and Kettle (TV. Br. Ph, Conf., 1914, 357), the important analytical data to be considered in valuing benzoin are (1) the percentage soluble in 90 per cent alcohol, and (2) the quantity of aromatic acids present, both free and combined. Methods of obtaining these factors are given in detail and also tables giving the results of such examinations of a number of commercial samples.

Sumatra Benzoin is sometimes heavily adulter-ated with stony debris, sand and bark. Schneider reports finding as much as 75 per cent of bark in a commercial article.

Uses.—Benzoin acts as a stimulating expec-torant, and was formerly employed in pectoral affections, but, except as an ingredient of the compound tincture of benzoin, it has fallen into disuse. It is frequently used as an inhalant in the treatment of inflammations of the respiratory tract such as laryngitis or bronchitis. Either the air of the chamber may be impregnated with its vapor by placing a small portion upon some live coals, or the patient may inhale the vapor of boiling water to which the balsam has been added. Its most frequent use, however, is an external antiseptic and protective. It is usually employed in the form of the compound tincture. In the East Indies, the balsam is burnt by the Hindus as a perfume in their temples of worship.

Dose, fifteen to thirty grains (1-2 Gm.)

Actions and uses from 1848 Christison and Griffith's Dispensatory;

Actions and Uses.—Benzoin, like other resinous substances, is a stimulant. It has been long held to possess expectorant and specific properties in chronic pectoral complaints, and constitutes a material part of most nostrums for these affections. Its reputation, however, has greatly declined of late years; and few now conceive it to be of much use, except as an agreeable addition to tinctures and mixtures for improving their taste and odour. Its best form is that of the Compound Tincture of Benzoin of the Pharmacopoeias,—a modification of a celebrated specific in all kinds of coughs, called Friar's-balsam. The reputation of the balsam as a pectoral remedy has been also transferred to its acid; which accordingly has a place in several officinal formulas. But the properties assigned to it are very problematical. It is much used in the composition of pastilles for fumigation. An approved preparation of the kind consists of powder of benzoin 16 parts, tolu-balsam 4, sandal-wood 4, labdanum 1, charcoal 48, nitre 2, tragacanth 1, and gum Arabic 2, well mixed together, then made into a strong paste with 12 of cinnamon-water, formed into little cones, and dried with a gentle heat (Henri and Guibort).
The, dose of its only preparation Tinctura benzoini composita, U.S. E. L. D. is fl. dr. i. ad fl. dr. ii.—Acidum Benzoicum. See that article.