The Constituents of Iris Versicolor.
The following extracts have been made from a thesis by WM. E. JENKS, Ph.G.
The recently collected rhizome of blue flag imparts a disagreeable nauseous acrid taste to water by decoction, and more decidedly to alcohol and ether. The acrimony as well as the medicinal virtues gradually diminish by age. The fleshy rhizome transversely sliced and dried in an atmosphere heated to 100°F., then pulverized and placed in darkened well-closed vessels excluded from light and air, will have its therapeutic properties unimpaired for a great length of time.
The oleoresin of blue flag is readily obtained by exhausting the rhizome in moderately fine powder with alcohol, sp. gr. .835, and distilling off the alcohol, the heat being carefully regulated towards the latter part of the operation. It is a dark reddish-brown liquid of a thick viscid consistence, and of a peculiar odor and acrid astringent taste. On treatment with ether and subsequent evaporation, it was comparatively free from astringency, more acrid and lighter in color.
The residue remaining after treatment with ether possessed a somewhat saccharine taste, was readily soluble in water and, with Trammer's test, showed the presence of glucose.
The powder exhausted by alcohol was percolated with water, and yielded a transparent reddish-brown liquid having a very astringent and scarcely acrid taste. Ferric chloride produced a blue black color, and with gelatin solution a gelatinous precipitate was obtained. Alcohol yielded a voluminous precipitate of gum which was readily soluble in water, and in this solution gelatinized with ferric chloride. The presence of albuminous matter and, in the decoction, a starch was likewise proven.
The thesis of D. W. CRESSLER, Ph.G., treats of the chemical constituents of the rhizome; the following is a synopsis of his results:
After macerating five troyounces of the coarsely powdered blue flag with water and then distilling a minute quantity of volatile matter was obtained as a brownish viscid mass, by agitating the distillate with chloroform and evaporating the latter. The decoction left in the retort was found to contain sugar, gum, tannin and starch.
Sixteen troyounces of the drug were exhausted with 95 per cent. alcohol, the tincture was concentrated by distillation and then treated with water acidulated with acetic acid; the precipitate, after washing and drying, weighed 1,990 grains, or about 25 per cent. It was freely-soluble in ether, chloroform and hot solution of caustic soda, and from the latter reprecipitated by hydrochloric acid.
The acid filtrate, after concentration, gave evidences of the presence of an alkaloid on testing with potassium iodo-hydrargyrate and solution of iodine in potassium iodide. On shaking the acid liquid with ether and evaporating the latter a brown viscous mass remained, which, was but slightly soluble in dilute acetic acid, and this solution was not affected by Mayor's test or by iodine. The acid liquid previously treated with ether was rendered alkaline with soda and agitated with amylic alcohol, on the evaporation of which a brownish viscid mass remained, which was almost entirely soluble in dilute acetic acid, the solution yielding precipitates with Mayor's test and with iodine.
For obtaining a larger quantity of the alkaloid 32 troyounces of the drug were digested with water acidulated with hydrochloric acid; the filtered liquid was concentrated, again filtered, the gummy matter removed by alcohol, the decanted liquid distilled, concentrated and rendered alkaline by soda. After agitation with ether, the etherial liquid separated readily on the addition of a few drops of alcohol and on evaporation yielded an amorphous mass, which was soluble in acidulated water, and this solution yielded precipitates with Mayor's test, iodine, tannin and picric acid.
The constituents of the rhizome are a volatile matter, starch, gum, tannin, sugar, an acid resin, fixed oil and very probably an alkaloid.