Pipitzahoic Acid * or Vegetable Gold.
(* Now called Perezone)
BY THOMAS GREENISH, F.C.S.
The author refers to the root and the acid exhibited by Mr. Vigener, of Bieberich, at the meeting of the German Apotheker Verein, in 1883; among the specimens of acid was one in fine flakes, the result of sublimation, and of a brilliant golden yellow color, hence the name "vegetable gold" applied to this product. The drug was first noticed in Europe in 1855, when Dr. Schaffner, a young German pharmacist, obtained of Dr. Leopold Rio de la Loza, Professor of Chemistry and Pharmacy in Mexico, a sample of the acid, which was subsequently analyzed by M. C. Weld ("Annal. Chem. Pharm.," xcv, 188). (A notice of the drug is also contained in 'Compt. Rend,' xlii, 873,1072. Ramon de la Sagra refers the root to Dumerilia (Perezia, Grey) Humboldtii Lessing, and describes the product as riolozinicacid.—EDITOR AMER. JOUR. PHAR.) In his report on the chemical and pharmaceutical products in the Philadelphia Exhibition, Mr. J. R. Jackson mentions pipitzahoic acid and pipitzahuina and briefly describes the former. (The Mexican Catalogue of the Exhibition of 1876 gives the following information: Trixis Pipitzahoac, Schaffner, "Pipitzahoac." In the valley of Mexico and in the western mountains. The rhizomes and roots contain a resinous substance, which Mr. L. Rio de la Loza has called pipitzoic acid. It is used as a drastic in a dose of from 4 to 8 grains.—EDITOR AM. JOUR. PHAR.)
The author then gives the following description of specimens presented by Mr. Vigener:
The roots, as furnished me, were in pieces from 8 to 10 cm. long and 2 mm. thick, externally of a brown or reddish brown color, more or less furrowed longitudinally on the surface, apparently through the shrinking of the root in the process of drying; its taste was decidedly bitter, leaving a pungency on the tongue which remained after the bitterness had passed off, and this pungency was somewhat persistent.
In a transverse section of the root the yellow spots of pipitzahoic acid were visible to the naked eye, and more distinctly seen in their relation to the other parts when the section was slightly magnified with a lens. The outer cortical layer consists of a double row of thickened tabular cells, tangentially disposed and deeply colored; this is followed by a layer, several cells deep, of collenchymatous tissue passing inward to the fundamental parenchyma of the root. The pipitzahoic acid is contained in secreting cells, in groups of from three to five; the acid is in yellow lumps of a crystalline structure. These depositories of the acid, striking in the entire section, are arranged in a circle and correspond to the fibro vascular bundles. Stellate spots are scattered throughout the fundamental tissue from the collenchyma to the centre of the root and are due to certain cells only of the tissue becoming thickened by secondary deposit, and converted into sclerenchymatous or stone cells with laminated structure, the intercellular spaces being filled with a dark colored deposit. These cells are found mostly single, but occasionally in groups of two, three or more. A longitudinal section shows, in addition to the relative positions of the cells referred to, the more characteristic constituents of the root as pipitzahoic acid, and the dark deposit around the long stone cell traversing the length of the root.
Most of the parenchymatous cells contain grains of inulin, Perezia being one of the Compositae, and containing inulin as the equivalent of starch present in the plants of other orders.
This brief account of the microscopical structure of the Perezia root will serve to make the more salient features in its histology intelligible. The quantity of root placed at my disposal was only 2 gm., and that of acid 0.33 gm.; it must, therefore, be obvious that few experiments beyond those afforded by micro-chemistry could be undertaken.
A transverse section of the root in which the lumps of pipitzahoic acid were visible were subjected to micro-sublimation on a microscopic glass slide, and at a little over 100°C. the acid sublimed on the cover-glass in yellow crystals. An alcoholic tincture of the root, yellow from solution ,of the acid, brought into contact with a dilute solution of caustic alkali or alkaline carbonate, developed that fine purple color which induced Herr Vigener to suggest a probable future for the acid as a color indicator in chemical investigations. The tincture on evaporation yielded crystals of pipitzahoic acid.
I was unable to satisfy myself as to the character of the intercellular dark deposit. It was not affected by alcohol, ether, benzol, chloroform or turpentine; neither did caustic alkali dissolve it; it was decomposed by nitric acid. If from the negative results of these experiments I may be allowed to offer an opinion, it would be that the deposit in question is dried latex.
When the pipitzahoic acid first came under my notice it occurred to me as probable that its formation might be due to a degradation of tissue and a rearrangement of its elements similar to that which takes place in araroba or goa powder; but a careful anatomical investigation does not support that view. It appears to be a true secretion in certain cells occupying the same relative position throughout the root, and unaccompanied by any of that breaking down of the surrounding cells so marked in the microscopical investigation of araroba.
The Perezia may prove a valuable medicinal plant, but to determine that point there are yet wanting those careful therapeutic investigations which should precede the appearance in general practice of any new drug, a series of well conducted experiments which very few seem capable of conducting, and for the results of which still fewer have the patience to wait.—Phar. Jour. and Trans., March 1, 1884.