July 14 2024

Medicinal uses of kinnikinnick(Arctostaphylos uva-ursi)


Kinnikinnick(<em>Arctostaphylos uva-ursi</em>)

kinnikinnick or pinemat manzanita is a shrubby species of the Ericaceae family. It is distributed by most of Europe, Asia and North America, although it can be found even in arctic or subarctic regions. A sample of the spread of this shrub are the testimonies of its consumption by the Carrier Indian tribe, which inhabited the northern part of British Columbia in Canada [1]. In the Iberian Peninsula can be found in the eastern half, except in the Balearic Islands.

Do not have high requirements of soil, but prefers sandy or rocky areas. It is located preferably between 500 and 2400 meters of altitude.

Leaves of Manzanita(Arctostaphylos glauca), a shrubby species native to California, have similar properties to those of bearberry, and are used for the same therapeutic purposes.

Varieties and synonymy     

Bearberry have been cataloged in several varieties:

Adenotricha, coactilis, leobrewer, longipilosa, marinensis, monoensis, pacifica, stipitata, etc.


Bearberry, red bearberry, bear's-grape, bear's bilberry, bear's whortleberry, foxberry, upland cranberry, mountain cranberry, crowberry, mealberry, rock-berry, mountain box, kinnikinnic, killikinic, universe vine, brawlins, burren myrtle, creashak, sagachomi, rapper dandies (fruit).

It is an evergreen shrub that spreads its branches forming like lawns creeping as shoots spreading on the floor or hanging from the trunk. Bearberry spreads easily, completely covering the land it occupies. The leaves are small, fleshy, dark green, 4 centimeters long by 1 wide. The flowers are small, globular, white or pink and are grouped in clusters. The fruit is a bright red berry, cranberry-like.

Flowering: It occurs in the middle months of the spring (April and May) although under favorable conditions runs from March until June. The fruits ripen in late summer and first half of autumn .

Harvest: The leaves are harvested at any time of year. Recent studies suggest that the best time for harvesting could be the autumn. In that time, arbutin content reaches its maximum concentration [2].


Leaves contain two hydroquinone glycosides, arbutin (6.3-9.16%) and methylarbutin. The glycosides content varies according to the origin of the preparation and collection station. Arbutin is hydrolyzed to hydroquinone, a substance with urinary tract antiseptic properties. However, some opinions hold that the crude extract of bearberry has more antimicrobial activity than arbutin.

Other important substances are tannins, that belong to catechins group (10-20%, according to sources) and flavones derived from quercetin. Like other plants, contains triterpenes such as ursolic acid.

The TLC has detected more than 300 substances in the essential oil of the plant: Besides terpenoids, carotenoids, fatty acids and derived substances. The essential oil has a relatively high amounts of L-terpineol and linalool (4.7-17.0%) [3].

Traditional applications     

According to military survival manuals, berries are edible, both raw and cooked, although have a tasteless and dry flavor. These same texts suggest preparing a refreshing infusion with the tender leaves of the plant.

Are attributed to this plant the following properties: astringent, diuretic, tonic, favoring urination and urinary tract disinfectant. By this reason it has been recommended for use in case of cystitis, pyelitis and urethritis. The bearberry would be activated only if the urine is alkaline, so it was recommended to take simultaneously sodium bicarbonate to reinforce its effect or if urine is acid.

Of the plant, the part used are the leaves, which are macerated in cold. There are numerous commercial preparations based on bearberry, especially in the form of infusions that are usually used as disinfectants urinals. Phenolic glycosides would confer these properties [4]. Arbutin would be hydrolyzed in the digestive tract, becoming hydroquinone, which is the agent that produces the urinary antiseptic effect.

The high tannin content would be responsible for astringent effect.

Traditional use cover, besides its use as a diuretic, the healing effect for treatment of wounds and ulcers and as local antiinflammatory for skin and mucous membranes.

Other uses include to smoke leaves, tanning of leather or making dyes.

Not for use during pregnancy. The preparations of bearberry can have an irritating effect on the stomach, so it should not be used in people who have any gastroduodenal disease.

Potential Consumers of this plant should know that under the name of Arctostaphylos uva-ursi are sold similar plants, although not with the same properties (for example, Arctostaphylos pungens). These species are used for herbal products or dietary supplements under the name bearberry[5].

Clinical Studies     

Have been published some studies on the metabolism of arbutin, but there are no published controlled studies of efficacy and/or safety of use of bearberry or any of its major components.

Arbutin is mainly hydrolyzed to hydroquinone sulfate and glucuronide. More than half of the administered dose is excreted in the urine within 4 hours as these compounds. That fraction reaches 75% after 24 h[6][7].

Experimental studies     

According to experimental studies, arbutin has antioxidant properties and can also produce hypopigmentation or depigmentation[8][9]. Several studies show antiinflammatory effects, either alone or as an adjunct of other substances (NSAIDs, corticosteroids)[10][11][12][13][14]. A study on an experimental model of bladder cancer concludes that arbutin inhibits proliferation of cell lines of human bladder cancer[15].

Arctostaphylos family plants inhibit melanin synthesis, via blocking tyrosinase. The methanolic extract of arbutin and bearberry have this same property[16][17].

Ethanolic extract of bearberry inhibits bacterial growth of susceptible strains of Neisseria gonorrhea[18].

This plant inhibits pancreatic lipase in experimental models, thus preventing intestinal absorption of fat[19].

Corilagin, a substance found in bearberry extract, reduced the minimum inhibitory concentration of some beta-lactam antibiotics such as oxacillin and cefmetazole, between 100 and 2000 times against strains of methicillin-resistant Staphylococcus[20].

The aqueous extract of Arctostaphylos uva-ursi increases urinary flow in laboratory animals, but does not sodium excretion[21].

A study to determine the ability of prevention of kidney stones of various plants concluded that the potential benefits of these would be due to some disinfectant action[22].

In mouse experimental diabetes, bearberry reduces some symptoms (polyphagia, polydipsia, weight loss) but not biochemical parameters of disease[23].

Bearberry, at concentrations as low as 50 ppm, due to its high tannin content, has shown molluscicidal properties against biophalaris glabrata, intermediate host of schistosomiasis[24].

Interactions and adverse reactions     

Are possible serious adverse reactions by confuse bearberry with atropa belladonna resulting in poisoning due to this last plant[25].

It has been shown in vitro inhibition of CYP3A4 and CYP19 from almost all derived from the bearberry, except methanolic extract. These isoenzymes are essential in the metabolism of many drugs. It can be important a possible inhibition of the P-glycoprotein system[26].

It has been described at least one case of a bull's eye maculopathy due to toxic effect of bearberry, linked to its ability as melanin inhibitor [27]. This case affected to a 56 year old woman who was taking bearberry for three years before the disease became apparent; initially manifested by a loss of visual acuity.


Although traditional uses and some experimental studies support therapeutic qualities of this plant, there are no published clinical trials with solid data and methodology as, for example, clinical trials with control group or other prospective studies that could support its efficacy and safety. So, without denying this possibility, can not be said that bearberry derivatives are effective and safe for use in patients.


1: Ritch-Krc EM, Thomas S, Turner NJ, Towers GH. Carrier herbal medicine: traditional and contemporary plant use. J Ethnopharmacol. 1996 Jun;52(2):85-94.
2: Parejo I, Viladomat F, Bastida J, Codina C. A single extraction step in the quantitative analysis of arbutin in bearberry (Arctostaphylos uva-ursi) leaves by high-performance liquid chromatography. Phytochem Anal. 2001 Sep-Oct;12(5):336-9.
3:Jahodár L, Leifertová I, Lisá M. Investigation of iridoid substances in Arctostaphylos uva-ursi. Pharmazie. 1978 Aug;33(8):536-7.
4: Radulovic N, Blagojevic P, Palic R. Comparative study of the leaf volatiles of Arctostaphylos uva-ursi (L.) Spreng. and Vaccinium vitis-idaea L. (Ericaceae).Molecules. 2010 Sep 2;15(9):6168-85.
5: Gallo FR, Multari G, Pagliuca G, Panusa A, Palazzino G, Giambenedetti M, Petitto V, Nicoletti M. Bearberry identification by a multidisciplinary study on commercial raw materials. Nat Prod Res. 2012 Jun 20. Molecules. 2010 Sep 2;15(9):6168-85.
6: Quintus J, Kovar KA, Link P, Hamacher H. Urinary excretion of arbutin metabolites after oral administration of bearberry leaf extracts. Planta Med. 2005 Feb;71(2):147-52.
7: Schindler G, Patzak U, Brinkhaus B, von Niecieck A, Wittig J, Krähmer N, Glöckl I, Veit M. Urinary excretion and metabolism of arbutin after oral administration of Arctostaphylos uvae ursi extract as film-coated tablets and aqueous solution in healthy humans. J Clin Pharmacol. 2002 Aug;42(8):920-7.
8: O'Brien NM, Carpenter R, O'Callaghan YC, O'Grady MN, Kerry JP. Modulatory effects of resveratrol, citroflavan-3-ol, and plant-derived extracts on oxidative stress in U937 cells. J Med Food. 2006 Summer;9(2):187-95.
9: Bol'shakova IV, Lozovskaia EL, Sapezhinskii II.[Antioxidant properties of plant extracts]. Biofizika. 1998 Mar-Apr;43(2):186-8.
10: Lee HJ, Kim KW. Anti-inflammatory effects of arbutin in lipopolysaccharide-stimulated BV2 microglial cells. Inflamm Res. 2012 Aug;61(8):817-25.
11: 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 Sep;112(9):673-7.
12: 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 Apr-May;111(4-5):253-8.
13: Matsuda H, Nakata H, Tanaka T, Kubo M. [Pharmacological study on Arctostaphylos uva-ursi (L.) Spreng. II. Combined effects of arbutin and prednisolone or dexamethazone on immuno-inflammation]. Yakugaku Zasshi. 1990 Jan;110(1):68-76.
14: 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 Jan;110(1):59-67.
15: Li H, Jeong YM, Kim SY, Kim MK, Kim DS. Arbutin inhibits TCCSUP human bladder cancer cell proliferation via up-regulation of p21. Pharmazie. 2011 Apr;66(4):306-9.
16: Matsuda H, Higashino M, Nakai Y, Iinuma M, Kubo M, Lang FA. Studies of cuticle drugs from natural sources. IV. Inhibitory effects of some Arctostaphylos plants on melanin biosynthesis. Biol Pharm Bull. 1996 Jan;19(1):153-6.
17: Matsuda H, Nakamura S, Shiomoto H, Tanaka T, Kubo M. [Pharmacological studies on leaf of Arctostaphylos uva-ursi (L.) Spreng. IV. Effect of 50% methanolic extract from Arctostaphylos uva-ursi (L.) Spreng. (bearberry leaf) on melanin synthesis]. Yakugaku Zasshi. 1992 Apr;112(4):276-82.
18: Cybulska P, Thakur SD, Foster BC, Scott IM, Leduc RI, Arnason JT, Dillon JA. Extracts of Canadian first nations medicinal plants, used as natural products, inhibit neisseria gonorrhoeae isolates with different antibiotic resistance profiles. Sex Transm Dis. 2011 Jul;38(7):667-71.
19: Slanc P, Doljak B, Kreft S, Lunder M, Janes D, Strukelj B. Screening of selected food and medicinal plant extracts for pancreatic lipase inhibition. Phytother Res. 2009 Jun;23(6):874-7.
20: Shimizu M, Shiota S, Mizushima T, Ito H, Hatano T, Yoshida T, Tsuchiya T. Marked potentiation of activity of beta-lactams against methicillin-resistant Staphylococcus aureus by corilagin. Antimicrob Agents Chemother. 2001 Nov;45(11):3198-201.
21: Beaux D, Fleurentin J, Mortier F. Effect of extracts of Orthosiphon stamineus Benth, Hieracium pilosella L., Sambucus nigra L. and Arctostaphylos uva-ursi (L.) Spreng. in rats. Phytother Res. 1999 May;13(3):222-5.
22: Grases F, Melero G, Costa-Bauzá A, Prieto R, March JG. Urolithiasis and phytotherapy. Int Urol Nephrol. 1994;26(5):507-11.
23: Swanston-Flatt SK, Day C, Bailey CJ, Flatt PR. Evaluation of traditional plant treatments for diabetes: studies in streptozotocin diabetic mice. Acta Diabetol Lat. 1989 Jan-Mar;26(1):51-5.
24: Schaufelberger D, Hostettmann K. On the molluscicidal activity of tannin containing plants. Planta Med. 1983 Jun;48(2):105-7.
25: Cikla U, Turkmen S, Karaca Y, Ayaz FA, Turedi S, Gunduz A. An Atropa belladonna L. poisoning with acute subdural hematoma. Hum Exp Toxicol. 2011 Dec;30(12):1998-2001.
26: Chauhan B, Yu C, Krantis A, Scott I, Arnason JT, Marles RJ, Foster BC. In vitro activity of uva-ursi against cytochrome P450 isoenzymes and P-glycoprotein. Can J Physiol Pharmacol. 2007 Nov;85(11):1099-107.
27: Wang L, Del Priore LV. Bull's-eye maculopathy secondary to herbal toxicity from uva ursi. Am J Ophthalmol. 2004 Jun;137(6):1135-7.

Page updated: September 24, 2012.


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