Notes on the Xanthorrhoea Resins.


Read at the Pharmaceutical Meeting, April 19.

At the last pharmaceutical meeting a resin was exhibited under the name of gum acroides, and it was stated to be a new Australian product. Shortly afterwards, during a visit to New York, I made some inquiries in relation to this supposed new commercial article and was surprised to learn that at one wholesale drug house it had been in stock fully ten years ago, and subsequently I learned from Mr. Chas. Bullock that a quantity of the same article had been on hand at the store formerly kept by Mr. Daniel B. Smith more than a quarter of a century ago. It was evident from the information received that the resin was not a new article in this country, and on examination numerous notices of it were found, from which it became evident that the appellation acroides is a corruption of acaroides, and that the resin is identical with Botany Bay resin, which name is better known, at least to the writer. Dunglison's dictionary says of the genus Xanthorrhoea: "There are several species. Two resins are obtained from them; one, the yellow resin of Xanthorrhoea or of New Holland, resina lutea Novi Belgii, Botany Bay resin or gum, ac'aroid resin or gum, resina vel gummi acaroï'des, which probably resembles tolu and storax in medicinal properties; the other, the red resin of Xanthorrhoea or blackboy gum."

This quotation gives the various synonyms of the substance in question and points also to its origin. A tolerably full account of it and the allied resin or resins may be found in Pereira's Materia Medica, in Guibourt's Drogues simples, etc. The following notes are compiled from these and other sources.

The genus Xanthorrhoea belongs to the natural order of liliaceae, is confined to Australia and consists of shrubby or arborescent plants, somewhat palm-like in appearance and having at the summit dense tufts of very long, wiry, narrow, two-edged or somewhat triangular leaves, resembling grass leaves; hence the name grasstrees, by which the species are known in Australia. The leaves are used as fodder for cattle, and the somewhat sheathing base of the inner leaves and the buds are eatable and form, particularly when roasted, an agreeable article of food. From the centre of the leaf tuft there rises a long cylindrical scape, which terminates with a long spike of small white flowers situated in the axils of the imbricate bracts and producing triangular three-celled capsules, containing flatfish, hard, black seeds.

R. Brown (1810) described seven species, viz.: X. arborea, australis, hastilis, media, minor, bracteata and pumilio. The two first-named species are arborescent, while the third and fourth have short stems, that of X. hastilis being about four feet high, and is said to sometimes attain a diameter of one foot and then to be probably more than a century old, owing to its slow growth. The last three species named before are stemless, i. e., the stems remain buried in the soil or rise scarcely above ground.

All the species abound in a resinous juice which, on exposure, hardens and as obtained from the different species, undoubtedly differs in appearance and also in composition. Guibourt distinguishes three xanthorrhoea resins—one yellow, one brown and one red. The dark-colored resin is still ascribed by some authors to X. hastilis, but Drummond (1840) pointed out that an arborescent species, probably X. arborea, is in Australia called black boy, and the Pharmaceutical Society of Victoria state that X. australis (which is arborescent) yields a large quantity of a brilliant ruby-colored resin. On the other hand, the botanist Smith refers the yellow resin to X. hastilis and some other species. The last named is the X. resinosa of Persoon, and of it Acaroides resinifera is quoted as a synonym in Gray's Supplement. The name acaroid resin is thus explained. The different xanthorrhoea resins have been described more especially in regard to their uses in papers by Mr. Bedford as a polishing material in "Amer. Jour. Phar.," 1863, p. 453, 454, and by Mr. P. L. Simmonds, in the same journal, 1857, p. 226 to 228, and in 1866, p. 465 to 468; the papers last quoted refer chiefly to the use of the resin in the manufacture of illuminating gas. The resins seem to be obtained as natural exudations, the subterraneous portions of the plant producing them in some species, at least, apparently in great abundance; but resin is also found covering the base of the leaves and it is secreted in such quantity in the woody stems that after crushing the latter it may be sifted from the chips to the extent of a hundred-weight per diem by one laborer.

The acaroid resin which was first noticed in 1789 by Governor Phillips (Voyage to Botany Bay) is met with in tears and in large masses usually, on account of its brittleness, broken into irregular pieces. It is intermixed with portions of wood, stalks, earth, etc., and when fractured has a speckled or granitic character. The pure resin is reddish yellow; the commercial article is externally brownish yellow, and internally opaque and of a pure yellow color, resembling that of gamboge, but always much lighter. This color description by Guibourt agrees with the sample presented here; but since the resin is described by some authors as being of a deeper yellow than gamboge, it is evident that it must be sometimes collected from different species. Triturated with water, it does not form an emulsion. When fresh it has an odor analogous to that of poplar buds, but much more agreeable (Guibourt); to us the odor appears to approach very nearly that of benzoin mixed with a little storax. By age the odor becomes weaker and gradually disappears, but it is always developed on powdering or by fusion. The resin dissolves in alcohol, leaving only 0.07 of a gum insoluble in water and analogous to bassorin. When heated it gives off white vapors, condensing into brilliant small laminae, which Laugier regarded as benzoic acid, but which Stenhouse (1848) found to consist largely of cinnamic acid.

The brown resin has a more balsamic odor than the preceding; the tears are roundish, externally deep red-brown and resembling dragon's blood; but the fracture is shining, glass-like, and in thin splinters it is perfectly transparent and of a hyacinth-red color. It is completely soluble in alcohol and contains more volatile oil, rendering it viscous and somewhat adhesive.

The red resin is in distinct tears of a deep brown-red and sometimes externally bright red; its fracture is glass-like; thin splinters are transparent and ruby-red; it is completely soluble in alcohol, the ligneous intermixtures excepted, and its balsamic odor becomes always apparent on heating.

Regarding the composition of the Xanthorrhoea resins, Pereira quotes the analyses of Lichtenstein (1799), Schrader, Laugier, Widman (1825), Trommsdorff (1826) and Stenhouse (1848). Heated with manganic binoxide and sulphuric acid acaroid resin evolves the odor of oil of bitter almonds, and by the action of nitric acid it yields a large proportion of carbazotic (picric) acid with little nitrobenzoic and oxalic acid (Stenhouse). Trommsdorff found the volatile oil to be colorless, fragrant and of a pungent aromatic taste. The resin is soluble in solutions of the alkalies and alkaline earths. On dry distillation much carbolic acid is obtained, with a small quantity of a light oil, but according to Sommer no umbelliferon. In 1866, Hlasiwetz and Barth ascertained that acaroid resin on being treated with fusing potassa yields large quantities of paraoxybenzoic acid, and from the mother-liquor of the etherial solution a little resorcin and pyrocatechin was obtained, together with the double compound of protocatechuic and paraoxybenzoic acids—C14H12O7.2H2O, which had been previously obtained from benzoin.

Three different xanthorrhoea resins were found by Hirschsohn (1877) to be incompletely soluble in chloroform and ether, but to dissolve completely in alcohol, the solutions acquiring a brown-black color with ferric chloride. The solution of the acaroid resin is yellow and yields with lead acetate a precipitate, while the solutions of the other two resins are red, that of X. quadrangulare being not disturbed by acetate of lead, while that of X. arborea produces with the same reagent a turbidity; the chloroformic solution of the latter is yellow, that of the former colorless.

The xanthorrhoea resins have been repeatedly suggested as possessing some value in perfumery; but they appear to be inferior for this purpose to benzoin, storax and the balsams of Peru and Tolu. Their medicinal properties appear to be likewise not well marked. As early as 1795 acaroid resin was said by Kite to neither vomit, purge nor bind the belly, nor to act materially as a diuretic or diaphoretic. Dr. Fish ("Boston Journal," x, p. 94) employed it in the form of tincture with opium in fluxus hepaticus and the colliquative diarrhoea of phthisis, and it has been recommended in chronic catarrhs. A tincture of acaroid resin, which has been given in doses of 1 - 2 drams, mixed with milk or a mucilaginous liquid, has been recommended to be made of equal weights of the resin and alcohol, and according to another formula of resin 2 ounces to alcohol 16 ounces. If used at all, the latter formula would appear to furnish a preparation of proper strength.

The American Journal of Pharmacy, Vol. 53, 1881, was edited by John M. Maisch.