Benzoinum, B.P. Benzoin.

Botanical name: 

Related entry: Benzoic acid

Benzoin is a balsamic resin obtained from Styrax Benzoin, Dryander, and probably other species of Styrax (N.O. Styraceae), trees that are indigenous to Siam, Sumatra, and Java. It is also official in the U.S.P. Normally the trees do not produce benzoin, or any substance analogous to it, but the infliction of a wound sufficiently severe to injure the cambium results in the formation of numerous oleoresin ducts, in which the secretion is produced. It is, therefore, a pathological product. The trunk of the tree is usually hacked with an axe, and after a time the liquid benzoin either accumulates beneath the bark or exudes from the incisions. After the exudation has sufficiently hardened, it is collected and exported, either in the form of loose pieces (tears), or in masses packed in oblong boxes or in tins. Several commercial varieties of benzoin are known, of which Siam and Sumatra benzoins are the most important.

Siam benzoin is collected in the Siamese province of Luang Prabang, but the tree which yields it has not yet been identified. It is sent into the market either as tears or masses. The tears are flattened or curved, and attain as much as 5 centimetres in length, and 12 millimetres in thickness; externally they are reddish-yellow, but internally milky-white. Lump or block Siam benzoin consists of tears, cemented together with a comparatively large proportion of transparent reddish-brown resin; both kinds are characterised by their agreeable odour, recalling vanilla, and by the fact that they contain benzoic acid, but not cinnamic acid.

Sumatra benzoin is obtained from S. Benzoin on the island of Sumatra. It is always exported in blocks, which, like the Siam variety, consist of white tears, compacted together by a resin, but the latter is usually less vitreous in appearance, and of a dull reddish or greyish-brown colour. Fine qualities have a strong storax-like odour, which is quite distinct from the vanilla odour of Slam benzoin. Sumatra benzoin may also be distinguished from Siam by the presence in it of cinnamic acid, which may be detected by boiling a little of the powdered resin with potassium permanganate, when an odour of benzaldehyde will be developed. Some samples of Sumatra benzoin are distinguished by their greyish, vitreous, or glassy appearance, and absence of any perceptible aromatic odour; these are classed as "Penang," or "Glassy Penang" benzoin, and are not suitable for pharmaceutical use. Palembang benzoin is another variety obtained from Sumatra, but from what tree is not definitely known. The drug arrives usually in tins, and consists of a reddish resinous mass, in which a few scattered tears are embedded. It has only a slight odour, resembling that of Sumatra benzoin, and, like the glassy Penang variety, is used chiefly for the production of benzoic acid.

Constituents.—The chief constituent of Siam benzoin is benzoic acid (up to 38 per cent.), partly free, partly combined with benzoresinol and siaresinotannol; it also contains vanillin (about 0.15 per cent.), and an oily, aromatic liquid (0.3 per cent.), which is probably an ester of benzoic acid. When quite pure it should be entirely soluble in alcohol, and yield only traces of ash. Good commercial Siam benzoin should yield not more than 3 per cent. of matter insoluble in alcohol, or more than 1 percent. of ash when incinerated. Sumatra benzoin contains 18 per cent. or more of benzoic acid, and about 20 per cent. of cinnamic mid, the latter partly free and partly combined with benzoresinol and sumaresinotannol; it also contains 1 per cent. of vanillin, styrol, styracin, phenyl-propyl cinnamate, and benzaldehyde, all of which combine to produce its characteristic odour. It is liable to be much adulterated with vegetable debris and mineral matter, and should not yield more than 10 per cent. insoluble in alcohol, or more than 2 per cent. of ash.

Action and Uses.—Benzoin has the action of its constituents, benzoic acid, cinnamic acid, and resins. It is used externally, in the form of tincture diluted with water, as a mild stimulant and antiseptic in irritable conditions of the skin. It acts as a carminative when taken by the mouth, is rapidly absorbed, and, during excretion, is mildly expectorant, diuretic, and antiseptic to the urinary passages. It is employed by inhalation with steam, chiefly as compound tincture of benzoin with or without aloes, in laryngitis and bronchitis. Benzoin is a preservative of fats otherwise liable to become rancid, and is therefore used in the preparation of Adeps Benzoatus.


Lotio Benzoini, B.P.C.—BENZOIN LOTION. Syn.—Lait Virginal.
Tincture of benzoin, 1; rose water, to 40. Employed as a cosmetic for the skin. It is sometimes prepared with the addition of 4 per cent. of glycerin.
Lotio Benzoini Composita, B.P.C.—COMPOUND BENZOIN LOTION.
Tincture of benzoin, 6; tincture of quillaia, 3; Cologne spirit, 6.25; distilled water, to 100. This lotion is an excellent toilet preparation.
Nebula Benzoini Composita, B.P.C.—COMPOUND BENZOIN SPRAY.
Oil of pine, 1.5; oil of eucalyptus, 3; oil of cassia, 1.5; menthol, 1; glycerin, 50; tincture of benzoin, to 100. Used in a nebuliser as a spray to the nose and throat in catarrhal affections of the respiratory passages.
Nebula Benzoini Composita cum Cocaina et Quinina, B.P.C.—COMPOUND BENZOIN SPRAY WITH COCAINE AND QUININE.
Cocaine hydrochloride, 0.75; camphor, 3; quinine hydrobromide, 6; antipyrine, 0.75 compound benzoin spray, to 100. Used in a nebuliser as a sedative and antiseptic in hay fever and coryza.
Tinctura Benzoini, B.P.C.—TINCTURE OF BENZOIN. Syn.—Simple Tincture of Benzoin. 1 in 10.
When mixed with water the resinous constituents of this tincture are precipitated; in the absence of salts, the precipitate is fairly diffusible and a suspending agent need not be added if the amount of tincture be small (1 in 40). If a larger quantity of tincture is present or the lotion contains salts, mucilage of gum acacia must be added, amounting to about one-sixteenth of the bulk of lotion. As the presence of mucilage of gum acacia in lotions is objectionable it should be used as sparingly as possible. Dose.—2 to 4 mils (½ to 1 fluid drachm).
Tinctura Benzoini, U.S.P.—TINCTURE OF BENZOIN, U.S.P.
Benzoin, in No. 40 powder, 20 alcohol (95 per cent.), sufficient to produce 100. Average dose.—1 mil (15 minims).
Tinctura Benzoini Composita, B.P.—COMPOUND TINCTURE OF BENZOIN. Syn.—Friar's Balsam.
Benzoin, in coarse powder, 10; Socotrine aloes, 1.83; prepared storax, 7.5; balsam of tolu, 2.5; alcohol, sufficient to produce 100. Macerate the ingredients with 80 of the alcohol for two days, with frequent agitation; then filter, and pass sufficient alcohol through the filter to make up to the required volume. The compound tincture is used as an antiseptic and styptic dressing for small cuts by applying undiluted upon lint. It is used with hot water for inhalation in bronchitis and inflammatory conditions of the pharynx and larynx, and is given internally in chronic bronchitis. When mixed with water, the resinous constituents of compound tincture of benzoin are best suspended with a mixture of equal parts of mucilage of gum acacia and mucilage of tragacanth, the total amount of mucilage used equalling one-eighth of the bulk of mixture. Dose.—2 to 4 mils (½ to 1 fluid drachm).
Tinctura Benzoini Composita, U.S.P.—COMPOUND TINCTURE OF BENZOIN, U. S. P.
Benzoin, in No. 40 powder, 10; purified aloes, in No. 40 powder, 2; storax, 8; balsam of tolu, 4; alcohol (95 per cent.), sufficient to produce 100. Average Dose.—2 mils (30 minims).
Tinctura Benzoini Composita sine Aloe, B.P.C.—COMPOUND TINCTURE OF BENZOIN WITHOUT ALOES.
Same as B.P. compound tincture, but without aloes. Used in the preparation of Vapor Benzoini.
Compound tincture of benzoin without aloes, 1; water, at 60°, 200. Quantity sufficient for one inhalation 600 mils (1 pint). Used in chronic bronchitis, and in pharyngitis and laryngitis. It is sometimes made twice the above strength.

The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.