Styrax Praeparatus, B.P. Prepared Storax.
Related entry: Balsam of Peru
Prepared storax (Styrax, U.S.P.) is a balsam obtained from the trunk of Liquidambar orientalis, Miller (N.O. Hamamelideae), a tree indigenous to the south-west of Asiatic Turkey. The secretion of storax, which is not a normal production of the tree, is induced by beating the bark. The injury thus inflicted on the cambium results in the formation of numerous oleoresin ducts, in which the balsam is secreted, and from which it is discharged into the wounded bark. The latter is then removed and the balsam separated by pressing, boiling with water, again pressing, and finally separating from the aqueous layer. Thus obtained it forms an opaque, greyish, viscid liquid, which on standing separates into a supernatant, aqueous liquid and a dark-brown, oleo-resinous layer; it contains about 20 to 30 per cent. of water, together with fragments of bark, etc. From these it is purified by solution in alcohol, filtration, and evaporation. The purified balsam is a translucent, brownish-yellow semi-liquid, with a strong, aromatic odour and taste. It is rendered more fluid by heating, but should give off no moisture. When it is boiled with solution of potassium bichromate and sulphuric acid, benzaldehyde is formed. Prepared storax is completely soluble in alcohol, ether, chloroform, carbon bisulphide, and glacial acetic acid. It yields on incineration less than 1 per cent. of ash.
Constituents.—The balsam is composed of a resin mixed with an oily liquid. The resin consists of storesinol, partly free and partly combined with cinnamic acid. The oily liquid contains styrol, ethyl cinnamate, phenyl-propyl cinnamate, cinnamyl cinnamate (styracin), vanillin, and free cinnamic acid. The specific gravity at 100° is 1.109 to 1.114. Cold petroleum spirit extracts about 25 to 45 per cent., and the acid number of the extract is low (40 to 60), whereas if coniferous resin be present the extract is larger in quantity and the acid number rises to 100 or even more; the ester value of the petroleum spirit extract is 124 to 160.
Action and Uses.—Prepared storax closely resembles balsam of Peru in its action. An ointment prepared with benzoated lard (1 in 4) is used as a parasiticide in scabies and other parasitic skin affections.
