Uva ursi is a fruit-bearing plant traditionally used to treat urinary tract infections and improve urinary health. Native Americans have used this plant for hundreds of years.
Modern researchers have discovered that uva ursi’s ability to fight infection is due to several bioactives present in the plant, namely arbutin and hydroquinone. The plant also contains tannins that have astringent effects, helping to shrink and tighten mucous membranes in the body. In turn, this effect helps reduce inflammation and fight infection (1).
Uva ursi has general antibacterial properties. In one comparison study, an aqueous extraction of uva ursi (leaf and berry) appeared to have inhibitory properties in vitro against the growth of Staphylococcus aureus. While it performed less potently than the reference antibiotics, vancomycin and tetracycline, it did out perform most of the other tested herbals (2).
Uva ursi may help treat inflammation of the bladder. Cystitis is inflammation of the bladder, typically caused by a bladder infection. It is a common type of urinary tract infection especially in women, that often gets better on its own when cases are mild. Some people who experience frequent episodes of cystitis may require long-term treatment.
In one study, researchers evaluated uva ursi’s ability to prevent recurrent cystitis. Fifty-seven women who had experienced at least three episodes of cystitis during the year preceding the study were treated with either an extract or placebo for 1 month.
At the end of the 1-year follow-up period, a statistically significant difference between groups in the number of recurrences was seen; none of the women taking uva ursi developed a bladder infection, while 5 of the untreated women did.
No side effects were reported, but continual use as a means of preventing infections is not recommended due to safety concerns and toxicity associated with extended use (3).
Medical professionals stress that despite this plant’s popularity for treating bladder infections, double-blind, placebo-controlled trials are needed to discover whether use of uva ursi actually helps people with established urinary tract infections (4).
Uva ursi has shown other potential anti-inflammation activity. Administration of a 50 percent methanol extract of the leaves (100mg/kg body weight) in mice inhibited picryl chloride-induced ear inflammation. The extract also increased the efficacy of prednisolone and dexamethasone (steroids prescribed to treat inflammation) in mice (5).
Uva ursi has antioxidant properties. A team of Pakistani researchers recently conducted laboratory studies to evaluate the antioxidant properties of several widely used medicinal plants, including uva ursi. The methanol extracts of the plant exhibited extremely significant antioxidant properties.
Antioxidants counter the effects of free radicals, which are believed to be responsible for a variety of illnesses, and also play a role in the cellular damage associated with aging.
In a 2013 issue of Journal of Pharmacognosy and Phytochemistry, researchers reported that uva ursi extract — at a concentration of 100 milligrams per milliliter — showed total antioxidant activity of 91.85 percent. Uva ursi may have anti-cancer properties. Researchers at the Chung-Ang University College of Medicine (South Korea) launched a recent investigation to examine the effects of arbutin, extracted from the plant, on human bladder carcinoma cells.
In different concentrations that are higher than 500 microg/ml, arbutin significantly decreased cancer cell proliferation in a time-dependent manner. Arbutin also strongly disrupted the cell cycle (6).
Arbutin may also be an effective melanoma treatment. Melanoma is the most dangerous form of skin cancer most often caused by ultraviolet radiation from the sun or tanning beds.
Uva ursi may help treat coughs. Arbutin (50-100mg/kg body weight) was found to be as active as codeine (10mg/kg body weight) in relieving coughs in cats (7).
In addition, arbutin led to the inactivation of the extracellular signal-regulated kinase, which is known to critically regulate cell proliferation (8).
Uva ursi may be effective as a skin fading cream. Extracts of the leaves have been widely used in cosmetic preparations to lighten the skin (due to age spots, acne scars or discoloration), with the active principles being hydroquinone and its derivatives. Application of 250µg arbutin to a human skin model appears to possess melanin-inhibiting properties.
These properties seem to apply to uva ursi as well; a 50 percent ethanolic extract of the leaves appears to inhibit melanin synthesis in vitro. Therefore, uva ursi, through arbutin, appears to have melanin-inhibiting properties and may confer whitening effects on the skin when topically applied (9).
Human studies assessing its efficacy and potency against other skin-lightening drugs are needed.
There are significant safety concerns with uva ursi.
High-dose and long-term use (more than two to four weeks) are strongly discouraged because they have been associated with liver damage and eye problems. It is likely safe for short-term use in adults, but it may cause nausea, vomiting and urine discoloration in some people.
Early evidence shows uva ursi possibly acting as a diuretic in the body, affecting levels of certain drugs (such as lithium) in the blood stream.
In addition, it should not be taken by young children, pregnant or nursing women, or those with severe liver or kidney disease.
Researchers believe the herb works best when a person’s urine is alkaline since acid destroys its antibacterial effect. Supplementation should not last longer than one to two weeks.
While it is believed that uva ursi works best at the first sign of urinary tract infection, more research is needed to see if it works in humans (10).
Due to these safety concerns, it is advised to speak to a physician before taking uva ursi in any form.
Uva ursi is a plant that has been traditionally used in Native American cultures for hundreds of years for the treatment of urinary tract infections and for general urinary health. Modern studies reveal that the bioactives present in this plant — arbutin and hydroquinone — give it its infection-fighting activity.
Tannins also present are believed to help shrink and tighten mucous membranes in the body, which in turn reduces inflammation and fights infection. Rich in antioxidants, uva ursi is also being studied for its antibacterial properties and for its ability to treat certain cancers, coughs and skin conditions such as age spots and discoloration.
There is a major concern of its safety, especially with long-term use. High-dose and long-term use (more than two to four weeks) have been associated with liver damage and eye problems.
Due to these safety concerns, it is advised to speak to a physician before taking uva ursi.