Arctostaphylos uva- ursi Common name: Bearberry, Uva ursi, Kinnikinnick
Parts used: Leaves
Constituents: Hydroquinone glycosides (4-15%): arbutin, methylarbutin. Polyphenols, hydrolyzable tannin, flavonoids (quercetin), resin, acids (ursolic, gallic, ellagic), allantoin, volatile oil (triterpene alkaloids).
Medicinal actions: Urinary antiseptic, anti-bacterial, astringent, anti-inflammatory, diuretic, tonic, oxytocic, hemostatic, demulcent.
Medicinal use: Is used primarily in the treatment of cystitis, ulcerations of the kidney and bladder, and to soothe and tonify these organs. Apart from its value in removing excess water from the body, it has a specific antiseptic and astringent effect upon the membranes of the urinary system. It will generally soothe, tone, and strengthen them. Specifically it is used where there is gravel or ulceration in either the kidney or the bladder. It may be used in the treatment of infections, or as part of a holistic approach to more chronic kidney problems. With its high astringency it is used in some forms of bed wetting. As a douche it may be helpful in vaginal ulceration and infection.
- Hydroquinone derivative, arbutin releases aglycone in alkaline urine with antimicrobial action.
- Tannins (hydrolyzable type) are astringent.
Pharmacy: Dry herb: up to 12g QD (equivalent to 400-840 mg arbutin) as infusion or cold macerate. Tincture: (1:5, 25%), 2 – 4 ml TID. Pulse dosing required (2 weeks max). Douche or topical wash.
Contraindications: Artostaphylos should be avoided during pregancy due to an oxytocic effect. Considering the tannin content, use should be avoided in organic kidney disease. Avoid use for longer than 14 days consecutively.
Toxicity: The toxicology is proportional to the conversion of arbutin to hyrdroquinone as hydroquinone is a highly toxic and mutagenic. 15 g of the fresh leaves can provide 1 g of hydroquinone which can be toxic with signs and symptoms of: tinnitus, nausea, vomiting, sense of suffocation, shortness of breath, cyanosis, convulsions, delirium and collapse. Caution due to hydrolyzable tannin content.
Interactions: None known.
Note: Hydroquinone is released from the glycoside arbutin in the gut, then conjugated to glucuronide in the liver for excretion by the kidney. Hydroquinone spontaneously dissociates from glucuronide in the urine if the pH is sufficiently alkaline. It can then kill bacteria. It is relatively difficult to acidify the urine, although high doses of vitamin C and cranberry juice will do this transiently in a minority of people. Therefore the combination of Uva-ursi and cranberry or vitamin C is sometimes considered to be contraindicated, although there is not good evidence that this causes a problem in most people.