Analysis of Hydrangea Arborescens.
By C. S. BONDURANT.
Read at the Pharmaceutical Meeting, February 22.
This indigenous plant grows abundantly in a large section of the United States. Considerable quantities are furnished to the market from Ohio and Indiana. Hydrangea is well known by its vernacular name "Seven Barks," and is said to have been used by the Cherokee Indians and subsequently by more scientific practitioners, some of whom regarded it as a specific in treatment of urinary calculi.
As far as I am able to learn hydrangea has received but little attention as to its proximate constituents.
The first analysis was probably that of Mr. Jos. Laidley, of Richmond, Va., in 1850. He mentions having found only gum, starch and resin.
The AMER. JOUR. OF PHAR., of April, 1881, p. 157, contains an essay by Mr. Jacob Baur, Ph. G., who claims to have found in addition to gum, starch, resin and sugar, an alkaloid in small quantity and tannin, also a crystallizable body, but was unable to separate a sufficient amount to determine its character.
In following the scheme outlined by Dragendorff, for plant analysis) I found a distinctly crystalline body in both alcoholic and ethereal extracts, the latter containing the largest, quantity. Its extraction and purification was attended with much difficulty, owing to the fact of its readily undergoing decomposition, which was accompanied by a resin-like body, possessing an odor entirely different from that characteristic of the drug.
A portion of the body, distinctly crystalline and freed from decomposition products, by solution and recrystallization from ether, was examined as to its chemical relations. The alkaloidal reagents were applied, none of which gave any evidence of alkaloidal character. After boiling an aqueous solution of the body with dilute hydrochloric acid and neutralizing with potassium hydrate, Fehling's solution was promptly reduced. Its behavior to Fehling s solution and the proneness to decomposition into the resin-like body and glucose, are sufficient evidence of its being a glucoside.
In order to obtain a larger quantity 500 grains of the drug were prepared and percolated to exhaustion with 95 per cent. alcohol. The greater portion of the alcohol being recovered by distillation, the concentrated extract was allowed to evaporate spontaneously, which left a viscid brownish red mass. After shaking with petroleum spirit to remove a fixed and volatile oil, the residue was treated with a slightly acidulated water and chloroform to remove the red coloring matter. The acidulated solution was shaken with ether several times, the ethereal washings on evaporation deposited the body in stellate clusters in fair state of purity.
After confirming its glucosidal character, the name hydrangin is proposed for it. On addition of an alkali to the aqueous solution a very distinct and strong opal blue fluorescence is observed, which is destroyed in acidifying. This characteristic fluorescent property was noticed in all the solvents used in exhausting the drug except the petroleum spirit and dilute hydrochloric acid.
From its fluorescent property it was thought to be similar to or identical with aesculin, a glucoside prepared from horse chestnut, but on comparison they were found to be distinct bodies. The fluorescence of hydrangin is opal blue, while that of aesculin is sky blue. Hydrangin also differs from aesculin by its ready solubility in ether its insolubility in strong hydrochloric acid and by its not being precipitated by argentic nitrate, mercuric chloride, nor neutral lead acetate. Hydrangin is not charred by concentrated sulphuric acid, but dissolves without color; also with nitric acid. A characteristic reaction for hydrangin is obtained on dissolving it in sulphuric acid and adding a small crystal of potassium bichromate when a dark purple color is produced which, after some minutes, fades to violet; and on addition of a few drops of water an olive green is produced which gradually fades.
Hydrangin melts at 235° C. and on increasing the temperature slightly, sublimes without decomposition, forming in stellate clusters, without color. It was desired to make an ultimate analysis of hydrangin, but owing to lack of time it will be reserved for future investigation.
In exhausting the drug with the usual solvents, there was found in the petroleum spirit extract, a fixed oil, turning dark reddish brown with concentrated sulphuric acid, saponifiable with potassa; and a volatile oil possessing the characteristic odor of the drug and evolving an alliaceous odor when treated with caustic potash and sulphuric acid. The presence of sulphur was indicated by the blackening of paper moistened with solution of lead acetate.
The ethereal extract contained in addition to the glucoside, a resin insoluble in water, sparingly soluble in chloroform, completely soluble in absolute alcohol and alkaline solutions.
Absolute alcohol extracted the glucoside, a resin insoluble in ether and a reddish coloring matter soluble in chloroform.
Water extracted vegetable mucilage, saponin and sugar.
The dilute soda solution contained mucilaginous substances and albuminoids.
Dilute hydrochloric acid extracted calcium oxalate in small quantities.
The residue boiled with dilute hydrochloric acid for some hours extracted starch by conversion into glucose.
Lignin was extracted by chlorine water with agitation.
The ash was found to be composed of sulphates, chlorides, carbonates, phosphates and silicates combined with calcium, iron, aluminium, magnesium and potassium.
|Petroleum spirit (fixed and vol. oil) .||2.28 per cent|
|Stronger ether (glucoside and resin)||1.57|
|Absolute alcohol (glucoside and two resins)||2.31|
|Distilled water (mucilage, saponin and sugar)||9.52|
|Dilute soda (mucilage and albuminoids)||8.37|
|Dilute hydrochloric acid (calcium oxalate)||1.40|
|Cellulose moisture, etc., undetermined||59.03|
No tannin was found to be present in the drug contradictory to statement made by Mr. Baur. The work above was done in the laboratory of the Philadelphia College of Pharmacy, under direction of Prof. Henry Trimble.