Supplement
Uva ursi, or bearberry, is a shrub whose leaves contain arbutin, which the body turns into the antimicrobial compound hydroquinone. People mostly look at it for bladder infections, and in one small trial of women with recurrent cystitis, none taking it had a recurrence over a year, versus 23% on placebo. The evidence is limited, though, and much of the other research is lab or animal work.
Sources: PMID 12162475; PMID 12522584
- Updated
- How we grade
- 16 studies cited
- Best evidence
- Grade C
- Conditions studied
- 1
- Outcomes
- 6
- Graded outcomes
- 0015
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
General
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Recurrent UTI Prevention A small double-blind placebo-controlled trial (Larsson et al. 1993, n=57 women with recurrent cystitis) found zero UTI recurrences in the uva ursi group versus 23% recurrence in placebo over 12 months. A pharmacokinetic study (n=16) confirmed 65-67% urinary excretion of arbutin metabolites in humans, supporting the antimicrobial mechanism. The EMA and German Commission E approve short-term use for lower urinary tract infections based on traditional evidence. | Changes; see studies | Moderate effect | 4 studies | 73 people | ||
Studies that measured recurrent uti prevention
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| Urinary Antimicrobial Activity In vitro studies demonstrate that arbutin is deconjugated by E. coli to release free hydroquinone with antimicrobial activity. A human pharmacokinetic study (n=16) confirmed substantial urinary excretion of hydroquinone and its conjugates after oral bearberry extract administration. However, a large RCT (ATAFUTI, n=382) found no significant benefit of uva ursi over placebo for acute uncomplicated UTI symptoms. | Improves (the measure goes up) | Small effect | 5 studies | 16 people | ||
Studies that measured urinary antimicrobial activity
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| Anti-inflammatory Effects A series of Japanese pharmacological studies in animal models found that bearberry leaf extract and its constituent arbutin enhanced the anti-inflammatory and antiallergic effects of corticosteroids (prednisolone, dexamethasone, indomethacin) on immune-mediated inflammation, including contact dermatitis and carrageenin-induced paw edema models. | Changes; see studies | Small effect | 5 studies | |||
Studies that measured anti-inflammatory effects
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| Diuretic Effect A rat study found that aqueous extract of Arctostaphylos uva-ursi increased urine flow, though without significantly increasing urinary sodium excretion, suggesting a mild diuretic mechanism distinct from typical saluretic agents. | Improves (the measure goes up) | Small effect | 3 studies | |||
Studies that measured diuretic effect | ||||||
| Tyrosinase Inhibition In vitro studies show that bearberry extract and isolated arbutin inhibit tyrosinase activity and melanin production from both dopa and dopachrome substrates. Multiple active constituents were identified including arbutin, gallic acid, and tannins. | Changes; see studies | Small effect | 3 studies | |||
Studies that measured tyrosinase inhibition
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| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Antioxidant Activity In vitro studies demonstrate strong radical scavenging capacity of bearberry leaf extract (90.4 mmol Trolox equivalents/g dry weight by ABTS assay), with ability to retard lipid oxidation in model food systems. Phytochemical profiling confirms high phenolic acid and tannin content contributing to antioxidant properties. | Improves (the measure goes up) | Small effect | 3 studies | |||
Studies that measured antioxidant activity
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Key findings
- Recurrent UTI PreventionChanges; see studies
- Urinary Antimicrobial ActivityImproves (the measure goes up)
- Anti-inflammatory EffectsChanges; see studies
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- Grade C
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Studies cited
16 studies from PubMed
- Study of the Properties of Bearberry Leaf Extract as a Natural Antioxidant in Model Foods.
- UHPLC-PDA-ESI-TOF/MS metabolic profiling of Arctostaphylos pungens and Arctostaphylos uva-ursi. A comparative study of phenolic compounds from leaf methanolic extracts.
- In vivo evaluation & safety profile evaluation of Arctostaphylos uva-ursi (L.) Spreng. extract in rabbits.
- Risk assessment of free hydroquinone derived from Arctostaphylos Uva-ursi folium herbal preparations.
- In vitro activity of uva-ursi against cytochrome P450 isoenzymes and P-glycoprotein.
- Bacterial deconjugation of arbutin by Escherichia coli.
- Urinary excretion and metabolism of arbutin after oral administration of Arctostaphylos uvae ursi extract as film-coated tablets and aqueous solution in healthy humans.
- Botanical medicines for the urinary tract.
- Effect of extracts of Orthosiphon stamineus Benth, Hieracium pilosella L., Sambucus nigra L. and Arctostaphylos uva-ursi (L.) Spreng. in rats.
- Anti-tyrosinase activity constituents of Arctostaphylos uva-ursi.
- Urolithiasis and phytotherapy.
- Pharmacological studies on leaf of Arctostaphylos uva-ursi (L.) Spreng. V. Effect of water extract on the antiallergic and antiinflammatory activities of dexamethasone ointment.
- Pharmacological studies on leaf of Arctostaphylos uva-ursi (L.) Spreng. IV. Effect of 50% methanolic extract on melanin synthesis.
- Pharmacological studies on leaf of Arctostaphylos uva-ursi (L.) Spreng. III. Combined effect of arbutin and indomethacin on immuno-inflammation.
- Pharmacological studies on leaf of Arctostaphylos uva-ursi (L.) Spreng. I. Combined effect of 50% methanolic extract and prednisolone on immuno-inflammation.
- Pharmacological study on Arctostaphylos uva-ursi (L.) Spreng. II. Combined effects of arbutin and prednisolone or dexamethazone on immuno-inflammation.