Examination of Ericaceous Plants.
BY EDWARD N. SMITH, PH.G.
From an Inaugural Essay.
Specimens of Chimaphila maculata, Pursh, Pyrola elliptica, Nuttall, P. chlorantha, Swartz, and P. rotundifolia, var. asarifolia, Michaux, were collected by myself during the months of June and July, 1880, carefully dried and powdered. With a view of ascertaining if they contained the same constituents as found in other ericaceous plants, I followed the process of Julius Jungmann ("Amer. Jour. Phar.," 1875, p. 202), by which he isolated the constituents of Uva ursi.
The coarsely powdered leaves were exhausted with water by percolation, the infusion heated to the boiling point and strained, when a flocculent coagulum of albumen was left on the strainer. The infusion was then concentrated and treated with freshly prepared hydrated oxide of lead. The precipitate was separated by a filter and the filtrate still more concentrated and divided into two portions; the first was set aside in a warm place to evaporate spontaneously, the second was treated with strong alcohol which produced a bulky precipitate.
The precipitate was separated by a filter and the alcoholic filtrate was divided into two portions; the first was set aside in a warm place to evaporate spontaneously, the second was evaporated to a syrupy consistence, then treated with ether and the ethereal solution evaporated at ordinary temperature. The residue consisted of a small quantity of crystals in prismatic needles mixed with a considerable quantity of resinous matter.
The alcoholic solution, after evaporation, yielded a dark colored extract which was re-dissolved in alcohol, then treated with animal charcoal, filtered and again evaporated at ordinary temperature. The residue contained a small quantity of acicular crystals.
The aqueous solution, after evaporation, yielded a soft extractive mass which was treated with a mixture of alcohol and ether; the solution was evaporated at ordinary temperature and yielded crystals in prismatic needles having a silky lustre.
All the crystals thus far obtained proved to be arbutin.
A second quantity of coarsely powdered leaves was boiled with water, the decoction strained and then treated with a concentrated cold aqueous solution of acetate of lead as long as a precipitate was thereby produced. The precipitate was separated by a filter and the filtrate treated with a solution of subacetate of lead until it no longer produced a precipitate; this was also separated by a filter and the filtrate freed from the lead by sulphuretted hydrogen, the sulphide of lead separated by a filter and the excess of sulphuretted hydrogen expelled by heating the filtrate. The filtrate was then evaporated to a syrupy consistence, re-dissolved in water and treated with animal charcoal, then filtered and again concentrated and while hot set aside. The solution, on standing, deposited crystals of arbutin in small bunches of needles of a white color.
Concentrated sulphuric or hydrochloric acid added to the crystals gradually dissolved them without change of color.
With nitric acid the crystals first turned black and then slowly dissolved, the acid assuming a yellow color and giving off fumes of nitrous acid.
A dilute aqueous solution of the crystals also produced the characteristic blue color with Jungmann's phosphomolybdic acid and ammonia test.
This test will also produce a blue color with solutions of morphia, aconitia, atropia and berberina, but not in such dilute solutions as is the case with arbutin, of which—according to Jungmann—1 part is distinctly indicated in 140,000 parts of water. The color is (in each case) dissipated by heat.
With a view to ascertain the value of this test, for detecting the presence of arbutin in plants without isolating it, experiments were made with the infusions of belladonna, aconite, berberis, digitalis, senna, lobelia, toxicodendron, absinthium, sabina and others. The infusions were diluted with sufficient water to make them perfectly colorless, then rendered alkaline with ammonia; but on the addition of phosphomolybdic acid they did not produce the characteristic blue color which is produced with infusions of the ericaceous plants known to contain arbutin.
EXAMINATION OF THE PRECIPITATES.
- The precipitate obtained on adding hydrated oxide of lead to the infusion of the leaves, and separating by a filter, was well washed and dried, then suspended in water and decomposed by sulphuretted hydrogen; the sulphide of lead was separated by a filter and the excess of sulphuretted hydrogen expelled by heating the filtrate. The filtrate was then concentrated and divided into two parts.
Part first was treated with a solution of gelatin, which produced a precipitate denoting the presence of tannin; the precipitate was separated by a filter and the filtrate treated with a neutral solution of ferric salts, which produced a bluish-black precipitate which disappeared on heating the solution, thus indicating the probable presence of gallic acid.
Part second, treated with a solution of calcium chloride and lime water, produced no precipitate, thus denoting the absence of tartaric acid; but, on heating the solution to the boiling point, a precipitate of calcium citrate was thrown down from the solution obtained from Chimaphila maculata, but no precipitate was produced with the solutions obtained from the plants of the genus Pyrola.
The solutions were then concentrated and treated with strong alcohol, which produced a precipitate of calcium malate in the solutions obtained from the plants of the genus Pyrola, but none in the solution which was separated from the citrate of calcium precipitate.
The organic acids as obtained by these investigations, therefore, are: In the plants of the genus Pyrola, tannic, gallic and malic acids, and in Chimaphila maculata, tannic, gallic and citric acids.
- The precipitate obtained by treating the concentrated infusion with strong alcohol was then treated with water in which it mostly dissolved; the solution was filtered and found to contain glucose by Trommels test.
The filtrate was then concentrated and again precipitated with strong alcohol; the precipitate was completely soluble in water and found to consist of gum and coloring matter.
- The precipitate obtained on adding a solution of acetate of lead to a decoction of the leaves, and separating by a filter,. was well washed, then suspended in water and decomposed with sulphuretted hydrogen, the sulphide of lead separated by a filter and the excess of sulphuretted hydrogen expelled by heating the filtrate. The filtrate gave a precipitate with gelatin; a dark green color with ferric salts; a reddish color with caustic alkalies, and a precipitate by Trommer's test.
- The sulphide of lead obtained on removing the excess of lead from the aqueous decoction of the leaves by sulphuretted hydrogen was first treated with hot water and then with hot alcohol, the solutions filtered and concentrated in a water-bath and, while hot, set aside. The aqueous solution, on standing, deposited a small amount of crystals of arbutin in small bunches of needles, but no crystals were obtained from the alcoholic solution.
On heating the mother liquors from arbutin with dilute sulphuric acid some ericolin was obtained as a brown-yellow resinous mass. It was stated by Jungmann to be soluble in alcohol but insoluble in water and could be purified by dissolving it in the former and precipitating by the latter. In experimenting with it, I found it to be soluble in both alcohol and water.
The leaves previously exhausted with water and dried were then exhausted with strong alcohol by maceration and percolation, and the dark green tincture thus obtained was evaporated, then treated with water and the residue washed with ether and dissolved in hot alcohol which, on cooling, deposited urson as an apparently amorphous mass, but on dissolving in hot alcohol microscopic needles were obtained.
Concentrated sulphuric acid turns the crystals black, the acid assuming a red color.
Concentrated nitric acid turns them yellow, giving off fumes of nitrous acid.
On distilling a quantity of the leaves with water, a distillate was. obtained which was neutral to test paper and had a tea-like odor, probably due to a small amount of volatile oil.
These investigations were performed with specimens of each of the plants, with nearly the same results.
The organic constituents of these plants, as obtained by these investigations, are therefore:
Arbutin, ericolin, urson, tannic, gallic and malic acids (in Chimaphila maculata, tannic, gallic and citric acids), gum, sugar, albumen, a small amount of volatile oil and some coloring: matter.