The dried leaves of Arctostaphylos Uva-ursi. From indigenous plants.

Uva Ursi, U.S.P. Uva Ursi. [Bearberry.] - The leaves of Arctostaphylos Uva-ursi,

Ericaceae Uvae Ursi Folia B P Bearberry Leaves 305

Fig. 206. - Uva Ursi.

Characters. - Obovate, entire, coriaceous, shining leaves, about three-fourths of an inch in length, reticulated beneath; with a strong astringent taste, and a feeble hay-like odour when powdered.

Composition. - Tannic and gallic acids, and a bitter neutral extractive - arbutin - which is soluble in warm water.

Adulteration. - Red whortleberry leaves.

Tests. - Leaves not dotted beneath nor toothed on the margin.

Preparations.

B.P.

Dose.

Infusum Uvae Ursi (1 oz. to 1 pint)......................................................

1-2 fl. OZ.

U.S.P.

Extractum Uvae Ursi Fluidum................................................................

30-60 min.

Uses. - Bearberry is an astringent and diuretic. It is chiefly used in catarrh of the bladder and of other parts of the genitourinary passages.

The utility of the leaves is probably due not to the tannic and gallic acids which they contain, but to the arbutin. This substance is partially excreted unchanged, and part of it is decomposed in the body, yielding hydroquinone (p. 809). The hydroquinone is excreted by the kidneys in combination with sulphuric acid. Hydroquinone-sulphuric acid is colourless and is not poisonous. It may become decomposed in the bladder, and the hydroquinone becoming oxidised will give a brown colour to the urine and impart to it antiseptic and stimulant properties, which are useful in catarrh of the bladder. The quantity of arbutin, in the infusion, is too small to be very useful, and yet if the infusion be made stronger it may disagree with the stomach. Pure arbutin is therefore to be preferred, and may be given in doses of 4 gr. or more, three or four times a day, either in powder or in solution.