Uva Ursi

Generic name: Arctostaphylos Uva Ursi (L.) Sprenge. Folium, Uvae Ursi Folium
Brand names: Achelblätter, Achelkraut, Arberry, Arctostaphylos, Bear's Grape, Bearberry, Beredruif, Berry Leaves, Brockberry, Busserole, Bärenkraut, Bärentraube, Bärentraubenblätter, Coralillo, Crowberry, Dogberry, Enab Edhdhib, Feuille De Busserole, Feuille De Raisin

Usage of Uva Ursi

Although clinical trials are lacking, uva ursi has been described for various conditions in pharmacopeias and used in traditional medicine as a mild urinary antiseptic for conditions such as cystitis, urethritis, and dysuria.WHO 2004

Antibacterial activity

Arbutin is the component of uva ursi thought to be most responsible for its antibacterial activity. Following ingestion of the leaves, arbutin is hydrolyzed to hydroquinone. Hydroquinone is then metabolized to glucoronate and sulfate esters, which are excreted in the urine and are responsible for the antiseptic and astringent actions in the urinary tract. Maximum antibacterial action is reached approximately 3 to 4 hours after ingestion and requires an alkaline urinary pH (pH>7).WHO 2004, Yarnell 2002

Experimental data

Extracts of uva ursi have inhibited the in vitro growth of Bacillus subtilis, EscheriChia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Serratia marcescens, Staphylococcus aureus, Streptococcus mutans, Proteus vulgaris, Staphylococcus faecalis, and Enterobacter aerogenes. In an in vitro study, healthy volunteers were given 0.1 to 1 g of arbutin orally. Urine samples were collected 3 hours later and adjusted to a pH level of 8 and, along with 20 other antibacterial compounds, tested against 74 bacterial strains including E. coli, Proteus mirabilis, P. aeruginosa, and S. aureus. Only Gentamicin, nalidixic acid, and arbutin (present in urine samples from subjects given arbutin 1 g) were active against all tested strains.WHO 2004

Clinical data

In a double-blind trial (preliminary report), an uva ursi extract or placebo was administered prophylactically for 1 month to 57 women with recurrent cystitis. In the 12 months following treatment, women who received uva ursi had no episodes of cystitis, whereas 23% of placebo-treated women had at least 1 episode of cystitis (P>0.05).Larsson 1993

In 382 adult women with uncomplicated suspected urinary tract infection, no difference was observed in symptom severity or antibiotic use between those in the uva ursi or placebo groups or in those advised or not advised to take ibuprofen. The study was a multicenter, 2x2 factorial, double-blind, randomized, controlled trial with 4 arms that consisted of 3- to 5-day use of uva ursi or control plus either no advice or advice to take ibuprofen. Follow-up consultations 1 and 3 months later also revealed no evidence of any difference among treatment groups.Moore 2019

Other uses

Extracts also have demonstrated in vitro antiviral activity against herpes simplex virus type 2, influenza virus A2, and vaccinia virus.WHO 2004

Uva ursi has been used in traditional medicine as a diuretic, to stimulate uterine contractions, and to treat diabetes, poor eyesight, renal or urinary calculi, rheumatism, and venereal disease. Topical applications have been used for skin depigmentation.WHO 2004 A controlled study in rats demonstrated significant diuretic activity at a dose of 50 mg/kg, but not at 100 mg/kg.Kurkin 2015 There are published reports demonstrating anti-inflammatory and antitussive activity in animals. Animal studies evaluating glucose-lowering effects and the effect on calcium excretion did not support these uses. Extracts of uva ursi leaves are widely used in cosmetic preparations for skin depigmentation.WHO 2004

An in vitro study evaluated the effects of arbutin on human bladder cancer cell proliferation. Arbutin decreased cell proliferation via extracellular signal-regulated kinase inactivation and p21 upregulation.Li 2011

Uva Ursi side effects

Ingestion of the dried leaves of uva ursi may cause a greenish-brown discoloration of the urine, which darkens upon exposure to air as a result of hydroquinone oxidation.WHO 2004

Ingestion of uva ursi leaves may cause nausea and vomiting due to its high tannin content.WHO 2004

Bull's eye maculopathy has been reported with long-term ingestion (3 years).Wang 2004

The WHO Monographs on Selected Medicinal Plants states that because of the risk of ochronosis, the hydroquinone concentration of topical preparations is limited to 2% in Nigeria, the United Kingdom, and the United States. Topical application has also caused leukoderma, erythema, and allergic contact dermatitis.WHO 2004

Before taking Uva Ursi

Avoid use. Uva ursi is contraindicated during pregnancy and lactation.WHO 2004

How to use Uva Ursi

Dosing and formulations of uva ursi products available in the United States vary. Doses of arbutin 400 to 840 mg have been used.

The WHO Monographs on Selected Medicinal Plants lists doses of 3 g in 150 mL as an infusion or cold macerate 3 to 4 times daily; 400 to 840 mg of hydroquinone derivatives; or other preparations accordingly calculated as arbutin.WHO 2004

Because uva ursi's antimicrobial activity can be blocked in acidic urine, ingestion of animal products or other foods known to acidify the urine should be decreased with its use. Administration of sodium or potassium bicarbonate may help to alkalinize the urine. Urinary pH should be greater than 7 for antimicrobial effectiveness. Treatment duration is generally limited to a few weeks because of carcinogenic concerns with long-term hydroquinone use.Yarnell 2002

Herbal teas

Various tea mixtures of uva ursi 1.5 to 4 g in combination with other herbs for the treatment of mild conditions of the urinary tract.EMA 2012

Powdered herbal substances

Six 500 mg tablets 4 times daily for adults and adolescents older than 12 years for inflammatory disease of the urinary tract (Germany); one 270 mg capsule 3 times daily as a diuretic (Spain); two 350 mg capsules twice daily to promote renal elimination of water, as an adjuvant to diuretics, and for treatment of benign urinary tract conditions (France).EMA 2012

Dry extracts

Two 500 mg tablets twice daily in adults and adolescents as a urinary antiseptic (Belgium); 2 tablets (239 to 298 mg [corresponding to 70 mg of hydroquinone derivatives]) 3 times daily (Germany); 4 to 5 tablets (114 to 143 mg [31.5 mg of hydroquinone derivatives]) 4 times daily (Germany); 2 to 3 tablets (228 to 315 mg [63 mg of hydroquinone derivatives]) 4 times daily (Germany); 2 tablets (425 to 520 mg [105 mg of hydroquinone derivatives]) 2 to 4 times daily (Germany). In all cases, these products are used for inflammatory disease of the urinary tract. Additional dry extract dosing regimens are four 215 mg tablets (40 mg of arbutin) 3 times daily for uncomplicated infection of the lower urinary tract when antibiotics are not considered essential (Poland); one 200 mg capsule twice daily to promote renal elimination of water and as an adjunct to diuretics (France).EMA 2012

Liquid extracts

101 to 207 mg of anhydrous arbutin 4 times daily to support treatment of inflammatory disease of the urinary tract (Germany).EMA 2012

Warnings

When taken orally, the median lethal dose (LD50) of hydroquinone is 300 to 1,300 mg/kg in rodents and dogs, and 42 to 86 mg/kg in cats. Nervous system toxicity (hyperexcitability, tremor, convulsions, coma) and death have been demonstrated with short-term administration of 1,300 mg/kg in rats.WHO 2004

While uva ursi leaves are not carcinogenic, hydroquinone may be carcinogenic.WHO 2004 A recommended therapeutic human daily dose of bearberry leaf extract (420 mg of hydroquinone derivatives calculated as anhydrous arbutin) liberates free hydroquinone in urine at a maximum exposure level of 11 mcg/kg of body weight per day. However, the daily exposure dose, below which there is negligible risk to humans, is 100 mcg/kg.de Arriba 2013

Fetal toxicity was noted in the offspring of rats fed arbutin 400 mg/kg. However, there were no effects on male or female reproduction or on fetal toxicity in rats fed up to 100 mg/kg of arbutin.WHO 2004

What other drugs will affect Uva Ursi

Urinary acidifying agents: Urinary acidifying agents may diminish the therapeutic effect of uva ursi. Consider therapy modification.(WHO 2004)

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