94. Styraceae.—Storax family.

428. Benzoinum.—Benzoin.

A balsamic resin obtained from Sty'rax ben'zoin Dryander, and other species of styrax.

BOTANICAL CHARACTERISTICS.—A large tree with tomentose branches. Leaves alternate, oblong, the under surface tomentose. Inflorescence compoundly racemose; calyx 5-toothed; corolla 5-parted, gray; stamens 10, their filaments coherent at the base into a short tube.

SOURCE AND VARIETIES.—Sumatra and Java. Sumatra-Penang, grayish-brown with many white tears, odor storax-like; Siam, reddish-brown, odor vanilla-like; Palembang resembles Sumatra, but yields more benzoic acid; false benzoin, catappa benzoin (Terminalia angustifolia), whitish brown.

A deciduous shrub of the Lauraceae, a native of Virginia, and called spice-wood or Benjamin tree, was at one time thought to be a source of benzoin. The berries of this tree are aromatic, and have been used as a substitute for allspice.

COLLECTION.—In Sumatra the benzoin is collected by making incisions in the tree during its seventh year, only the unhealthy trees yielding resin. The milky juice which flows first is the purest and most fragrant, but soon hardens upon exposure to the air. That which flows subsequently is brownish, and some is scraped out when the tree is cut down and split open, as it is soon killed by the process of tapping. These varieties are in common called head, belly, and feet benzoin, and have the relative value to each other of 105, 45, and 18, being esteemed according to their whiteness, semi-transparency, and freedom from admixture (Royle). A product of the younger tree furnishes a variety known as amygdalina benzoin, which contains whitish, almond-like tears diffused through its substance.

DESCRIPTION OF DRUG.—It exudes from incisions in the bark, hardening on exposure into agglutinated shining tears of a yellowish-brown or reddish-brown color; internally milk-white; usually, however, it is in various-sized pieces, having a resinous fracture, showing a mottled surface of smooth, shining white spots, tears, imbedded in the somewhat rough and porous, reddish-brown mass. It has a very agreeable odor and a slightly aromatic taste, leaving an irritating sensation in the mouth and fauces.

CONSTITUENTS.—Benzoin has the constitution of a balsam and is by some authors considered as a solid balsam; it contains resin, benzoic acid, C₇H₆O₂, 20 to 24 per cent., which comes off in dense white vapor when benzoin is heated and melted, and cinnamic acid, C₉H₈O₂ (in some varieties), detected by boiling in milk of lime, decomposing with HCl, and adding permanganate of potassium, when the odor of bitter almonds is given off. Siam benzoin contains vanillin, C₈H₈O₃, and has a vanilla-like odor. Sumatra Benzoin. Ash, not more than 2.5 per cent. Siam Benzoin. Ash, not more than 2 per cent.

Preparation of Benzoic Acid.—Obtained by simple sublimation of benzoin. Is also prepared artificially from toluol, but sometimes from phthalic acid or hippuric acid. Contamination with cinnamic acid is detected by mild oxidation when it yields the odor of oil of bitter almond.

ACTION AND USES.—Stimulant and diaphoretic, but seldom used as such except in the compound tincture of benzoin. It is used locally as a stimulant and irritant, and in tooth powders and fumigations. Dose: 9 to 30 gr. (0.5 to 2 Gm.).

OFFICIAL PREPARATIONS.

Tinctura Benzoini Composita (10 per cent., with aloes, storax, and tolu),. Dose: 15 to 60 drops (1 to 4 mils)

Tinctura Benzoini (20 per cent.) 10 to 40 drops (0.6 to 2.6 mils).

Adeps Benzoinatus (2 Gm. digested in 100 Gm. of lard).

A Manual of Organic Materia Medica and Pharmacognosy, 1917, was written by Lucius E. Sayre, B.S. Ph. M.