Uva Ursi. U. S. (Br.) Uva Ursi.
"The dried leaves of Arctostaphylos Uva-ursi (Linné) Sprengel (Fam. Ericaceae), without the presence or admixture of more than 5 per cent. of stems or other foreign matter." U. S. "Bearberry Leaves are the dried leaves of Arctostaphylos Uva-ursi, Spreng." Br.
Uvae Ursi Folia, Br.; Barren Myrtle, Mountain Box, Rock-berry; Kinnikinnic; Uva-ursi, Busserole, Raisin d'Ours, Fr. Cod.; Folia Uvae Ursi, P. G.; Bärentraube, Bärentrauben-blätter, G.; Uva Ursina, It.; Gayuba, Sp.
The uva ursi, or bearberry, is a low evergreen shrub, with trailing stems, the young branches of which rise obliquely upward for a few inches. The leaves are scattered, upon short petioles, from half an inch to an inch long, obovate, or oblong-spatulate, acute at the base, obtuse at the apex, entire, with a rounded margin, thick coriaceous, smooth, shining, deep green on their upper surface, paler and covered with a net-work of veins beneath; furnished especially near the margin or near the midrib with minute hairs, which are usually abundant in young leaves, but may be few or absent in old leaves, especially those which have been much handled. The flowers, which stand on short reflexed peduncles, are in small clusters at the ends of the branches. The calyx is small, five-parted, reddish, and persistent. The corolla is ovate or urceolate, reddish-white, or white with a red lip, transparent at the base, contracted at the mouth, and divided at the margin into five short reflexed segments. The stamens are ten, with short filaments and bifid anthers; the ovary round, with a style longer than the stamens, and a simple stigma. The fruit is a small, round, depressed, smooth, glossy red berry, with an insipid mealy pulp and five cohering seeds.
This humble but hardy shrub inhabits the northern latitudes and high mountains of Europe, Asia, and America. On the American continent it extends from Hudson's Bay as far southward as New Jersey and Pennsylvania, in some parts of which it grows in abundance. It prefers a barren soil, flourishing on gravelly hills and elevated sandy plains. The leaves are the only part used in medicine. They are imported from Europe, but are also collected within our own limits, and the market of Philadelphia is supplied to a considerable extent from New Jersey. They should be gathered in autumn, and only the green leaves selected. In Europe the uva ursi is adulterated with the inert leaves (... they're not inert. -Henriette) of the Vaccinium Vitis-Idaea L. (Cowberry, Mountain Cranberry); these may be distinguished by being obovate, having revolute margins which are sometimes slightly toothed, and the presence of fine blackish dots or bristly points upon their lower surface. Leaves of the Chimaphila umbellata (L.) Nutt., sometimes found among the uva ursi, may be readily detected by their greater length, their cuneiform-lanceolate shape, and their serrate edges.
Arctostaphylos glauca Lindl., manzanita, is a small tree or shrub indigenous in California, where it generally grows in dry and rocky places on the west of the mountain ranges. The leaves appear to possess properties similar to those of the official species. (See Flint, A. J. P., 1873, p. 187.) The fruit ofA. arguta Zucco , a Mexican species, is said to be a narcotic poison.
Properties.—Uva ursi is officially described as: "Usually more or less entire, laminae obovate or oblong-spatulate, from 12 to 30 mm. in length and from 5 to 13 mm. in breadth; summits obtuse or rounded; margins entire, slightly revolute; bases cuneate, tapering into short, stout petioles; upper surfaces dark green, glabrous and shiny, finely reticulate; under surfaces yellowish-green and slightly pubescent, especially on the midribs; coriaceous, fracture short; odor aromatic, tea-like; taste astringent and somewhat bitter. The powder is olive green; under the microscope it shows irregular fragments; epidermal cells polygonal, those of the lower surface showing broadly elliptical stomata about 0.035 mm. in length, surrounded by from 5 to 8 neighboring cells; cells of mesophyll with chloroplastids and frequently irregular masses of a carbohydrate; fragments of fibro-vascular bundles with spiral tracheae associated with narrow, strongly lignified sclerenchymatous fibers and frequently also with crystal fibers with mono-clinic prisms, from 0.006 to 0.015 mm. in diameter; numerous fragments made up of cells having a yellowish-brown content which are colored a bluish-black upon the addition of ferric chloride T.S. Place 0.1 Gm. of powdered Uva Ursi on a watch crystal and cover with another watch crystal and gently heat the powder; a crystalline sublimate forms, consisting of long rods and feather-like aggregates which polarize light with a brilliant play of colors. Macerate 1 Gm. of powdered Uva Ursi with 10 mils of boiling water, shake the mixture occasionally until cold and then filter it; the filtrate yields a grayish-purple precipitate upon the addition of a few drops of ferrous sulphate T.S." U. S.
"Obovate or spatulate, about two centimetres long, yellowish-green, coriaceous, entire, shortly petiolate. Upper surface glabrous, shining, reticulate; veinlets depressed. Slight odor; taste very astringent." Br.
The commercial drug frequently consists of the entire plants and therefore contains a large quantity of stems. The latter should not be present, according to the official definition, in greater amount than five per cent. Farwell states that the leaves are sometimes very dark or blackish-green, which is probably due to carelessness in drying. (M. R., xvii, p. 35.) Holm has contributed an interesting article on the morphology of the plant. (M. R., xx, p. 95.)
Uva ursi leaves contain—besides tannic and gallic acids, bitter extractive resin, gum, fatty matter, and salts of potassium and calcium—two glucosides, arbutin, C12H15O7, and ericolin, and a resinous principle, urson. The tannin is so abundant (6 or 7 per cent.) that the leaves are used for tanning in Russia.
Arbutin is somewhat widely diffused in the species of Ericaceae, such as Chimaphila umbellata (L.) Nutt., Chimaphila maculata (L.) Pursh, Epigaea repens L., and Gaultheria procumbens L. Kawalier (Chem. Gaz., 1853, p. 61) obtained it from uva ursi by precipitating the decoction with lead acetate, filtering, treating the liquid with hydrogen sulphide, again filtering, evaporating to the consistence of syrup, and allowing the product to stand for several days. This gradually assumed the form of a crystalline jelly, which, being placed upon linen so as to allow the mother liquor to drain off, and then pressed, yielded nearly colorless crystals, which were purified by solution in boiling water and treatment with animal charcoal. Arbutin thus obtained is in long, acicular, colorless crystals, united in tufts, and of a bitter taste. It is soluble in water, alcohol, and ether, unchanged apparently by a heat of 100° C. (212° F.), bat fusible at 167° to 168° C. (332.6°-334.4° F.), without action on vegetable colors, and not precipitated by ferric salts or by lead acetate or subacetate. It is a glucoside, being resolvable by emulsin, or more rapidly by boiling with sulphuric acid, into glucose and hydroquinone, C6H6O2 (arctuvine of Kawalier). The occurrence of methylhydroquinone among the products of decomposition led Hlasiwetz and Habermann to give the formula C25H34O14 to arbutin, but Schiff showed that this was because arbutin was almost always accompanied by methylarbutin, C12H15(CH3)O7+H2O. This compound has been made synthetically by Schiff (Ber. d. Chem. Ges., 1882, p. 1841) by acting upon arbutin with methyliodide and potassium hydroxide in methyl alcohol solution, and purely synthetically by Michael (Ber. d. Chem. Ges., 1885, p. 118) by the action of methylhydroquinone and acetochlorhydrose. It is decomposed by dilute acids into glucose and methylhydroquinone. Upon heating 1 part of arbutin with 8 parts of manganese oxide, 2 parts of sulphuric acid, and 1 part of water, it gives off the penetrating odor of quinone. The aqueous solution is rendered blue by a small quantity of solution of ferric chloride, and green by a larger quantity. No precipitate is produced by either acids or alkalies. It blackens ammoniacal solution of silver nitrate after boiling with diluted sulphuric acid, and throws down cuprous oxide from alkaline copper solutions upon heating. It dissolves in sulphuric acid, forming a colorless solution, turning red after a short time; a trace of nitric acid turns this solution yellow-brown. An aqueous solution (1 in 20) is not changed by hydrogen sulphide. A good test for arbutin is that of Julius Jungmann, as follows: When phosphomolybdic acid is added to a solution of arbutin previously rendered alkaline by ammonia or other alkali, a blue color is produced, which is deep when the solutions are strong, but observable even when they are very dilute. (A. J. P., May, 1871, p. 204.)
After the extraction of arbutin there is obtained from the mother liquor ericolin, C34H56O21. This is also found in many other ericaceous plants. It is glucosidal in nature and yields on decomposition, besides glucose, a volatile oil, ericonol. Another crystallizable principle has been discovered by Trommsdorf, who calls it urson, C30H48O3. It appears to be of a resinous character, although it can be obtained in silky needles, being tasteless and inodorous, insoluble in water, difficultly soluble in alcohol and ether, fusible, at a higher temperature volatilizable, and inflammable in the air. It is obtained by treating uva ursi with a very small quantity of ether by percolation, allowing the ether to evaporate, washing the crystalline extract with ether, and recrystallizing from alcohol. (A. J. P., xxvii, 334.)
A. G. Perkin has obtained from the leaves of uva ursi a yellow coloring principle of the composition C15H10O7, crystallizing in glistening yellow needles. On fusion with alkali, phloroglucinol and protocatechuic acid were formed. Though resembling quercetin in these points, it forms deep green solutions with diluted potassium hydroxide. (A. J. P., 1898, 584.)
Uses.—Uva ursi is used to-day almost exclusively in the treatment of catarrhs of the urinary tract, especially acute cystitis. Although by some it is believed to exercise an astringent and alterative influence on these membranes, it is probable that its action is simply that of a mild antiseptic. Lewin (V. A. P. A., 1883, xcii, p. 517) attributes its virtues to the arbutin which is decomposed in the system liberating hydro-quinone. Bass, however (Z. E. P. T., 1912, x, p. 120), is doubtful whether enough hydroquinone can appear in the urine to exercise any antiseptic effect. But whether or not its virtue is due to arbutin or some other principle, the clinical evidence is strong that uva ursi is a useful drug in these conditions. Formerly it was also employed in gravel, nephritis, urethritis, and menorrhagia, but has been largely abandoned. Because of the formation of hydroquinone in the body the urine often acquires a greenish color from the use of uva ursi.
Arbutin has been employed in medicine not only for its antiseptic effect but also as a diuretic in doses of from one to three grains (0.065-0.2 Gm.).
Dose, powdered uva ursi, from twenty grains to a drachm (1.3-3.9 Gm.), to be repeated three or four times a day; but the fluidextract is always preferred.