Bearberry (Arctostaphylos uva-ursi)
What is Bearberry?
Bearberry is a small shrub native to the temperate climates of North America and Europe. The leaves are almost exclusive for treating bladder and urinary tract infections but are also used to reduce inflammation topically and internally.
Bearberry is mainly used as a treatment for urinary tract infections, venereal disease, and prostatitis. Some of the glycosides contained in the leaves become active one passing into the urine, where the antimicrobial components can then take effect without being subjected to metabolism by the liver.
Although effective, bearberry must be used cautiously, and never more than five days in a row or more than three times a year.
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What Is Bearberry Used For?
The main uses of bearberry are for urinary tract infections, or inflammation. This can involve cystitis, vaginal infection, kidney calculi, and prostatitis.
Traditional Uses of Bearberry
Bearberry leaves have been used as an antiseptic since the 1200's in Europe. [7].
In North America, uva-ursi has been used as an addition to ceremonial smoking rituals, as well as for venereal disease and inflammation and infection of the urinary tract. [7].
Th Ecclectics used uva-ursi to treat chronic bladder irritations, enuresis, excessive mucous, blood in the urine, chronic diarrhea, dysentery, menorrhagia, leucorrhea, diabetes, chronic gonorhea, and strangury [7].
The berries of uva-ursi can be eaten as food, as well.
Uva-ursi has also been used to whiten skin and may be used treat hyperpigmentation disorders [7].
Bearberry has been used in the past to treat bed wetting [3], which is likely due to its well known astringing and tonifying actions to the urinary system.
The British herbal pharmocopoeia lists bearberry as a diuretic, urinary antiseptic, and astringent useful for cystitis, urethritis, dysuria, pyelitis, and lithuria [2].
Herb Details: Bearberry
Botanical Information
The Arctostaphylos genus contains 50 species. The uva-ursi species is named after the Uva-ursi constellation which takes the shape of a bear in Greek astrology.
It prefers well-draining mountainous slopes, but can also be found growing throughout rolling fields and pastures in temperate regions.
The flowers are small, pink, and bell-shaped arranged in drooping clusters. [7]. The leaves of bearberry are characteristically obovate, with a dark green top and silvery-grey bottom.
Habitat Ecology, & Distribution
Arctostaphylos is native to Europe, Asia, and the northern United States and Canada. The Arctostaphylos genus is distributed across the northern hemisphere. [2, 7].
It prefers to grow on rocky hills in the mountains but can be found in fields and near rivers or sandy beaches/dunes as well. Bearberry proliferated well after a fire, as the seeds are fire resistant and require cold treatment to germinate. In the absence of fires, it spreads mainly through vegetative growth. [6].
Harvesting Collection, & Preparation
Bearberry is usually prepared as an infusion or as a liquid extract. Cold water extraction is the preferred extraction technique in order to better preserve the arbutin, and helps to eliminate alot of the tannins, This would not be preferred in cases where it is primarily the astringent benefits that are desired of the plant.
Pharmacology & Medical Research
+ Antibacterial
The main source of the antibacterial activity of bearberry is hotly debated among researchers. Many consider the hydroquinone esters such as arbutin to be the main antibacterial source, while others suggest that it is instead the free hydroquinone that provides this activity. Nevertheless, the antibacterial effects of bearberry are well known and are especially useful for urinary tract infections. [7].
The antibacterial action of arbutin was found to correlate with beta-glucosidase activity inside bacteria. This is an enzyme that will convert arbutin into free hydroquinone. Streptococcus, Klebsiella, and Enterobacter were noted to have the highest activity of this enzyme. [7]. The hydroquinone that is a resulting metabolite from the phenolic glycoside arbutin affects the surface exposed adhesins, cell wall polypeptides, and membrane-bound enzymes [10].
Other components in bearberry are also suggested to support these effects including methylarbutin, tannins, gallic acid, ellagic acid, and numerous flavonoids, including quercetin, myricetin, and their glycosides, as well as the triterpenes b-amyrin and ursolic acid [10].
In one study, bearberry was found to be amongst the most active out of 14 different Canadian medicinal plants against Neisseria gonorrhoeae [1]. This is an important finding in light of a new strain of drug-resistant gonorrhea strain.
Uva-ursi has been noted to produce a stronger antibacterial action on the urinary tract when the urine is alkaline. Since the majority of cases of urinary tract infection produces acidic urine, it may be beneficial to alkalinize the urine alongside the application of uva-ursi. [7].
Phytochemistry
Flavonoids Iridoids, quinones, tannins, terpenoids, acids, resin, volatile oils.
Bearberry leaves contain hydroquinone glycosides (including arbutin and methylarbutin), iridoids (monotropein), polyphenols (mainly gallotannins), phenolic acids, flavonoids (quercetrin, iso-quercetrin, myricacitrin, and others), tannins, volatile oils, ursolic acid, malic acid, gallic acid, and triterpenes. [3, 4, 7].
The arbutin contained in the leaves, bark, and roots of uva-ursi forms a chemical called hydroquinone, which inhibits the growth of surrounding plants. Arbutin has also been noted to exist in many plants that have developed the ability to survive extreme and prolonged dehydration. [7]. Arbutin has also been reported to convert to hydroquinone in the bladder less efficiently with acidic urine. This is why many texts suggest alkalizing the urine along with the use of bearberry for best results as an antimicrobial [2].
Pharmacodynamics
Arbutin, one of the main components of bearberry (a phenolic glycoside), is hydrolyzed in the intestines to hydroquinone, absorbed, and metabolized where it's excreted in the urine. [8, 9].
Clinical Applications Of Bearberry:
Bearberries hydroquinone esters are useful for treating urinary tract infections. This is by far the best and most popular application of bearberry medicinally.
Cautions:
bearberry is not suitable for long term use. Limit to 5 consecutive days, and no more than 3 times per year.
Contraindicated with pregnancy, lactation, and children under 12.
Contraindicated with kidney disorders.
Synergy
Potential synergy with dandelion root or leaf.
Uva-ursi has been noted to produce a stronger antibacterial action on the urinary tract when the urine is alkaline. Since the majority of cases of urinary tract infection produces acidic urine, it may be beneficial to alkalinize the urine alongside the application of uva-ursi. [7].
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References:
Cybulska, P., Thakur, S. D., Foster, B. C., Scott, I. M., Leduc, R. I., Arnason, J. T., & Dillon, J. R. (2011). Extracts of Canadian First Nations Medicinal Plants, Used as Natural Products, Inhibit Neisseria gonorrhoeae Isolates With Different Antibiotic Resistance Profiles. Sexually Transmitted Diseases, 38(7), 667-671. doi:10.1097/olq.0b013e31820cb166
British Herbal Medicine Association. (1983). British Herbal Pharmacopoeia. Bournemouth, UK: Author.
Hoffmann, D. (2003). Medical herbalism: The science and practice of herbal medicine. Rochester, VT: Healing Arts Press.
Wren, R. C. (1968). Potter's new cyclopaedia of botanical drugs and preparations. Rustington, Sussex: Health Science Press for Potter & Clarke.
Bone, K. (2003). A clinical guide to blending liquid herbs: Herbal formulations for the individual patient. Edinburgh [u.a., MO: Churchill Livingstone.
Small, E., & Catling, P. M. (1999). Canadian medicinal crops. Ottawa: NRC Research Press. http://site.ebrary.com/id/10006178
Bone K, Mills S. (2013). Principles and Practice of Phytotherapy. Elsevier health. China. (Pg. 392-398).
Hansel R, Sticher O, Steinegger E. Pharmakognosie-Phytopharmazie. (1999). Berlin: Springer-Verlag,
Siegers C, Bodinet C, Ali SS, Siegers CP. (2003). Bacterial deconjugation of arbutin by Escherichia coli. Phytomedicine 2003;10:58–60.
Uva Ursi (Arctostaphylos uva-ursi): A Review of Clinical Therapeutics by the American Herbal Pharmacopeia (2015). Alternative And Complementary Therapies, 21(4), 180-181. doi:10.1089/act.2015.29013.uva