Uva Ursi

Scientific Name(s): Arctostaphylos uva ursi L. Sprengel. (Also referred to as Arbutus uva ursi L.). The related plants A. adenotricha and A. coactylis Fern et Macbr. have also been termed uva ursi by some authors. Family: Ericaceae (heaths)

Common Name(s): Uva ursi , bearberry , kinnikinnik , hogberry , rockberry , beargrape , manzanita.

Uses

Uva ursi has been used to treat urinary tract infections; as a diuretic; to treat induced contact dermatitis, allergic reaction-type hypersensitivity, and arthritis in conjuction with prednisolone and dexamethasone. However, research reveals very limited clinical data regarding the use of uva ursi to treat any condition.

Dosing

While there is no recently published clinical evidence to support specific dosage, uva ursi has been used for urinary tract infections at doses of up to 10 g of leaf daily, equivalent to 400 to 840 mg arbutin. 1

Contraindications

Ingestion of uva ursi in large doses has resulted in ringing of the ears, nausea, vomiting, cyanosis, convulsions, collapse, and death.

Pregnancy/Lactation

The published report of the Expert Advisory Committee in Herbs and Botanical Preparations to the Canadian Health Protection Branch (January 1986) recommended that food preparations containing uva ursi provide labeling contraindicating their use during pregnancy and lactation because large doses of uva ursi are oxytocic. 2 Avoid use.

Interactions

None well documented.

Adverse Reactions

Ingestion of uva ursi in large doses has resulted in ringing of the ears, nausea, vomiting, cyanosis, convulsions, collapse, and death. The product may also impart a green color to the urine and cause gastric discomfort.

Toxicology

Ingestion of 1 g of hydroquinone resulted in ringing of the ears, nausea, vomiting, cyanosis, convulsions and collapse. Death followed the ingestion of 5 g of hydroquinone. 2 These symptoms are rare; most commercial products have less than 1 g of crude uva ursi per dose.

Botany

Uva ursi is a low-growing evergreen shrub with creeping stems that form a dark green carpet of leaves. It can grow to 20 inches in height. The plant has small, dark, fleshy, leathery leaves and clusters of small white or pink bell-shaped flowers. It blooms from April to May and produces a dull orange berry. The plant grows abundantly throughout the northern hemisphere from Asia to the United States. 3 , 4

History

“Uva ursi” means “bear's grape” in Latin, probably because bears are fond of the fruit. Uva ursi was first documented in a 13th century Welsh herbal. 4 Teas and extracts of the leaves have been used as urinary tract antiseptics and diuretics for centuries. The plant has been used as a laxative and the leaves have been smoked. 5 Bearberry teas and extracts have been used as vehicles for pharmaceutical preparations. In homeopathy, a tincture of the leaves is believed to be effective in the treatment of cystitis, urethritis, and urinary tract inflammations. The berries are not used medicinally. They are juicy but have an insipid flavor that improves upon cooking. 6

Chemistry

The leaves contain hydroquinone derivatives, mainly arbutin and methyl-arbutin in concentrations ranging from 5% to 15%. HPLC determination of these substances has been evaluated. 7 Tannins are also present (6% to 40%) including hydrolysable, ellagic and gallic acid tannins. Because of this high concentration of tannin, teas prepared from this plant are generally made by soaking the leaves in cold water overnight. This minimizes extraction of the bitter tannins. A report on tannin isolation from uva ursi leaves is available. 8

Flavonoids including hyperoside, myricetin, quercetin, and glycosides such as hyperin, isoquercitrin, myricitrin, and quercitrin are also found.

Triterpenes, monotropein, piceoside, phenol-carboxylic acids such as gallic, p-coumaric, and syringic acids can be found. Terpenoids such as alpha-amyrin and ursolic acids are present in the plant, as malic acid, allantoin, resin, volatile oil, and wax. 2 , 3 , 4

Other chemistry includes the identification of 14 phenolic acids from uva ursi leaves using GLC; 9 isolation of 8 triterpenoids from uva ursi roots; 10 isolation and identification of free and bonded saccharides in the plant leaves; 11 and differentiation of adulterated uva ursi leaf samples. 12

Uses and Pharmacology

Antimicrobial effects

Arbutin is hydrolyzed in gastric fluid to hydroquinone. In alkaline urine, hydroquinone is mildly astringent and is an effective antimicrobial agent. Despite this activity, in practice, large amounts of uva ursi must be consumed for any significant effect to occur and the urine must be alkalinized. 13 Evidence suggests that arbutin itself may contribute to the antiseptic activity of the plant, because both arbutin and crude leaf extracts have been shown to possess mild antimicrobial activity in vitro. 14 A report discusses liquid concentration of uva ursi possessing antiseptic and diuretic properties. 15 Uva ursi aerial part extracts were found to be most active against Escherichia coli and Proteus vulgaris . 16

Animal/Clinical data

None.

Urinary tract effects

Antibacterial activity of arbutin causing urinary tract infection is caused by beta-glucosidase activity of the infective organism. 14 Uva ursi is one of the best natural urinary antiseptics and has been extensively used in herbal medicine. 4 The German Commission E monograph lists its use as “for inflammatory disorders of the lower urinary tract.” An herbal remedy including uva ursi is used to treat “compulsive strangury, enuresis, and painful micturition.” 3

Animal data

None.

Clinical data

One report discusses metabolite production of uva ursi, 17 other reports discuss bile expelling/lowering effects of the plant 18 and its beneficial effects on treatment of kidney stone formation. 19 Several plant compounds (ursolic acid and isoquercetin) are mild diuretics and contribute to the plant's diuretic effect. Uva ursi is a constituent in many over-the-counter herbal diuretic preparations. A report on bearberry reviews diuretic effects and other plant properties. 20

Other uses

Arbutin may increase inhibitory action of prednisolone and dexamethasone on induced contact dermatitis, allergic reaction-type hypersensitivity, and arthritis, suggesting uva ursi's therapeutic effects against immuno-inflammation. 21 , 22 , 23 , 24 Another study reports reduced hyperphagia, reduced polydipsia and reduced loss of weight in diabetes-induced mice given bearberry. There was no effect on glucose or insulin plasma concentrations, but it may be of some benefit in these diabetes symptoms. 25 Therapy of experimentally induced hepatitis in rats with extract of A. uva ursi has been reported. 19 , 26 Bearberry leaf was also found to be effective in inhibiting melanin production in vitro. 27

Dosage

While there is no recently published clinical evidence to support specific dosage, uva ursi has been used for urinary tract infections at doses of up to 10 g of leaf daily, equivalent to 400 to 840 mg arbutin. 1

Pregnancy/Lactation

The published report of the Expert Advisory Committee in Herbs and Botanical Preparations to the Canadian Health Protection Branch (January 1986) recommended that food preparations containing uva ursi provide labeling contraindicating their use during pregnancy and lactation because large doses of uva ursi are oxytocic. 2 Avoid use.

Interactions

None well documented.

Adverse Reactions

Products containing uva ursi may turn urine green. The plant's astringent tannin content may cause gastric discomfort and usually limits the dose ingested.

Do not use uva ursi if suffering from kidney disease. Do not take the plant for more than 7 to 10 days at a time. 4

Toxicology

Hydroquinone is toxic in large doses (oral LD-50 in rats is 320 mg/kg). 28 Ingestion of 1 g of the compound resulted in ringing of the ears, nausea, vomiting, cyanosis, convulsions and collapse. Death followed the ingestion of 5 g of hydroquinone. 2 These symptoms are rare; most commercial products have less than 1 g of crude uva ursi per dose. Doses up to 20 g of uva ursi have not caused pharmacologic responses in healthy individuals. 29

Bibliography

1. Blumenthal M, ed. The Complete German Commission E Monographs . Boston, MA: American Botanical Council, 1998.
2. Newall CA, Anderson LA, Phillipson JD. Herbal Medicine . London: Pharmaceutical Press, 1996.
3. Bisset NG. Herbal Drugs and Phytopharmaceuticals . Stuttgart, Germany: CRC Press, 1994.
4. Chevallier A. Encyclopedia of Medicinal Plants . New York, NY: DK Publishing Inc., 1996.
5. Spoerke DG. Herbal Medications . Santa Barbara, CA: Woodbridge Press Publishing Co., 1980.
6. Wild Edible and Poisonous Plants of Alaska , Univ. of Alaska Cooperative Extension Service. 1985.
7. Stambergova A, Supcikova M, Leifertova I. Evaluation of phenolic substances in Arctostaphylos uva-ursi. Part 4. Determination of arbutin, methylarbutin and hydroquinone in the leaves by HPLC. Cesk Farm . 1985;34:179–182.
8. Ostrowska B, Gorecki P. Investigations on possibility of utilization of Bergenia leaves to therapeutics in place of arbutin and tannin raw materials deficiency. Part 1. Phytochemical investigations. Herba Polonica . 1988;34:21–25.
9. Dombrowicz E, Zadernowski R, Swiatek L. Phenolic acids in leaves of Arctostaphylos uva ursi L., Vaccinium vitis idaea L. and Vaccinium myrtillus L. Pharmazie . 1991;46:680–681.
10. Jahodar L, Grygarova V, Budesinsky M. Triterpenoids of Arctostaphylos uva-ursi roots. Pharmazie . 1988;43:442–443.
11. Leifertova I, Jahodar J. Study of free and bonded saccharides in the leaves of Arctostaphylos uva-ursi. Farmaceut Obzor . 1989;58:507–511.
12. Schier W, Schultza W. Actual adulteration of medicinal crude drugs: bearberry leaves and sorrel herbs. Dtsch Apoth Zeitung . 1990;130:463–465.
13. Frohne D. The urinary disinfectant effect of extract from leaves uva ursi. Planta Med . 1970;18:1-25.
14. Jahodar L, Jilek P, Patkova M, Dvorakova V. Antimicrobial action of arbutin and the extract from the leaves of Arctostaphylos uva-ursi in vitro. Cesk Farm . 1985;34:174-178.
15. Zaits KA, Zozulya RN, Zaitseva LA. Liquid concentration of Uva ursi. Farmatsiia . 1975;24:40–42.
16. Holopainen M, Jahodar L, Seppanen-Laakso T, Laakso I, Kauppinen V. Antimicrobial activity in some Finnish Ericaceous plants. Acta Pharm Fenn . 1988;97:197–202.
17. Duskova J, Dusek J, Opantrna J. Effect of the organ origin of the explant and the degree of differentiation of the tissue culture of Arctostaphylos uva-ursi. Cesk Farm . 1991;40:83–85.
18. Azhunova TA, Sambueva ZG, Nikolaev SM, Matkhanov EI. Bile expelling effects of Arctostaphylos uva-ursi. Farmatsiia . 1988;37:41–43.
19. Grases F, Melero G, Costa-Bauza A, Prieto R, March JG. Urolithiasis and phytotherapy. Int Urol Nephrol . 1994;26:507–511.
20. Houghton P. Herbal products. Part 9. Bearberry, dandelion and celery. Pharm J 1995;255:272–273.
21. Kubo M, Ito M, Nakata H, Matsuda H. Pharmacological studies on leaf of Arctostaphylos uva-ursi (L.) Spreng. I. Combined effect of 50% methanolic extract from Arctostaphylos uva-ursi (L.) Spreng. (bearberry leaf) and prednisolone on immuno-inflammation. Yakugaku Zasshi . 1990;110:59–67.
22. Matsuda H, Nakata H, Tanaka T, Kubo M. Pharmacological study on Arctostaphylos uva-ursi (L.) Spreng. II. Combined effects of arbutin and prednisolone or dexamethasone on immuno-inflammation. Yakugaku Zasshi . 1990;110:68–76.
23. Matsuda H, Tanaka T, Kubo M. Pharmacological studies on leaf of Arctostaphylos uva-ursi (L.) Spreng. III. Combined effect of arbutin and indomethacin on immuno-inflammation. Yakugaku Zasshi . 1991;111:253–258.
24. Matsuda H, Nakamura S, Tanaka T, Kubo M. Pharmacological studies on leaf of Arctostaphylos uva-ursi (L.) Spreng. V. Effect of water extract from Arctostaphylos uva-ursi (L.) Spreng. (bearberry leaf) on the antiallergic and antiinflammatory activities of dexamethasone ointment. Yakugaku Zasshi . 1992;112:673–677.
25. Swanston-Flatt SK, Day C, Baily CJ, Flatt PR. Evaluation of traditional plant treatments for diabetes: studies in streptozotocin diabetic mice. Acta Diabetol Lat . 1989;26:51–55.
26. Sambueva ZG, Lonshakova KS, Nikolaev SM, Naidakova TA. Farmatsiia . 1987;36:40–45.
27. Matsuda H, Nakamura S, Shiomoto H, Tnaka T, Kubo M. Yakugaku Zasshi . 1992;112:276–282.
28. Woodard T, et al. Fed Proc , 1949;8:348.
29. Tyler VE. The Honest Herbal . Philadelphia, PA: G. F. Stickley Co., 1981.

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