Botanical name: Arctostaphylos uva ursi

Family: Ericaceae

Synonyms: Bearberry, Kinnikinnik

Part used: Dried leaf

MAJOR CHEMICAL CONSTITUENTS

The primary medicinally active constituent is arbutin, a phenolic glycoside that generates hydroquinone as a result of glycolysis. Tannins, and flavonoids are also present. A small amount of free hydroquinone is found in the leaves. P-coumaric acid and caffeic acid, compounds with known antibacterial properties, and salicylic acid, a known bacteriostatic and anti-inflammatory agent, may be of significance. Uva ursi contains the flavonoid quercetin and the triterpenes ursolic acid, among many other constituents.

PRINCIPAL USES

• Urinary tract antiseptic, bacteriostatic, anti-inflammatory, and astringent in the treatment of cystitis, urethri-tis, dysuria, and pyelonephritis.

• Topical astringent applied for postpartum vulvovaginal healing

TRADITIONAL AND HISTORICAL USES

Uva ursi was used by numerous native tribes of the northern United States and Canada as a diuretic or for treatment of inflammation of the genitourinary tract. It appears to have been introduced into European medical practice in the thirteenth century as a treatment for conditions of the bladder and kidney, and as such has remained in use since. Goethe is reported to have been prescribed and successfully treated for kidney stones with this herb. Early US medical botanists reported on its usefulness in the treatment of genitourinary disorders and by the late nineteenth century it was widely used by Eclectic physicians as an astringent tonic for chronic diarrhea, dysentery, and menorrhagia, as well as for genitourinary disorders and diabetes. It has had an official entry in pharmacopoeias of numerous western nations since the eighteenth century, including the British Herbal Pharmacopoeia, the National Formulary and the United States Dispensatory. It can still be found in the pharmacopoeias of numerous countries including Austria, Czechoslovakia, Egypt, France, Germany, Hungary, Japan, Russia, Switzerland, and others.

IN VITRO, ANIMAL, AND CLINICAL DATA

Uva ursi remains one of the most important and commonly used urinary tract disinfectants in modern herbal medicine, widely used in the treatment of uncomplicated acute and recurrent urinary tract infections. Midwives include the herb as an astringent anti-inflammatory in sitz baths and perineal rinses for postnatal perineal healing and as part of treatment of vaginitis and urethritis. There are few clinical trials or pharmacodynamic studies of uva ursi. In vitro studies using crude leaf preparations and extracts of uva ursi leaf have demonstrated mild antimicrobial activity against known UTI causing organisms, including but not limited to C. albicans, E. coli, S. aureus, and Proteus vulgaris, and others. Several studies have also demonstrated antiinflammatory activity of the herb, particularly enhanced when extracts are used in combination with anti-inflammatory pharmaceutical drugs, for example, prednisolone, indomethacin, or dexamethazone.

MECHANISMS OF ACTION

The mechanisms of action of uva ursi are not fully elucidated. It appears, however, that arbutin, and its agly-cone, hydroquinone — a urinary disinfectant — are primarily responsible for the herb’s antimicrobial activity. Hydroquinones are primarily hydrolyzed in the kidney because tannins prevent enzymatic activity that would normally lead to its conversion in the gut; it also appears that arbutin might be hydrolyzed in the urinary tract as a result of P-glucosidase activity stimulated by pathogenic infection. Arbutin is rapidly absorbed after consumption of tea and extract preparations, with urinary excretion of metabolites within a few hours and up to 24 hours. Antibacterial actions may be most prominent in an alkaline (pH urinary environment; however, activity is not necessarily dependent on elevated urinary pH.

RATINGS

• German Commission E: Approved for the treatment of inflammatory conditions of the urinary tract.

• Botanical Safety Handbook Class 2b and 2d rating: Not to be used in pregnancy, a caution that is reiterated by most authorities.

PREPARATIONS USED CLINICALLY

• Cold water infusion

• Hot water infusion

• Tincture

Uva ursi shows greater antibacterial activity in an alkaline environment; some authors suggest giving it along with sodium bicarbonate or substantially increasing fresh fruit and vegetable consumption during treatment to alkalinize the urine; others suggest avoiding the use of acidifying agents during treatment. Alkalinization of the urine seems not to be a prerequisite to the antiseptic properties of hydroquinone released from arbutin. Some amount of disagreement can be found in the literature regarding the requirement of an alkaline pH environment for the efficacy of this herb. Some authors postulate that a reduced urinary pH inhibits the efficacy of the herb; others argue that increasing the alkalinity of the urinary environment enhances the efficacy of the herb, while still others state that activity is not depend on urinary pH. Given the reliability of this herb generally, it is prudent to conclude that if uva ursi does not seem to be working, the addition of 2 “00″ capsules of sodium or potassium bicarbonate may be taken once or twice daily with uva ursi doses, to alkalinize the urine in such situations before making a final determination about efficacy. Some authors recommend discontinuing use of the herb after 7 days; however, the European Scientific Cooperative on Phytotherapy (ESCOP) recommends treatment be continued until complete disappearance of symptoms, up to a maximum of 2 weeks.

DOSAGE

Doses should provide the equivalent of 400 to 840 mg arbutin daily, divided over two to four doses.

• Hot or cold infusion: 1.5 to 4 g dried leaves to 150 mL water as a cold infusion steeped for 2 hours or as a hot infusion steeped 30 minutes, and taken up to four times daily.

• Tincture: 2 to 4 mL three to four times daily of a 1:5 preparation.

USE IN PREGNANCY AND LACTATION

Pregnancy

The Botanical Safety Handbook gives this herb a class 2b and 2d rating: Not to be used in pregnancy, a caution which is reiterated by numerous authorities. However, the reasons for contraindication are variable and not well supported, ranging from alleged uterotonic and oxytocic activity to “theoretical fetotoxicity.” The risk of oxytoxic effect is based on a single unreferenced anecdotal report by Brinker in Herb Contraindications and Drug Interactions, and has not been substantiated clinically. Limited evidence suggest that the herb has potentially fetotoxicity owing to its hydroquinone content. Studies using pure hydroquinone (i.e., not the herb in bulk or extract form) have produced microtubulin dysfunction in bone marrow, and exposure of human lymphocytes and cell lines and pure hydroquinone has been shown to cause genetic damage. Low potential for mutagenicity and negative Ames test have also been reported. In animals administered 100 and 400 mg/kg sc per day of arbutin, no signs of fetal toxicity were observed. Uva ursi has been used by midwives in the United States as a primary treatment of acute symptomatic cystitis in pregnancy for at least two decades, with no adverse reports associated with its use.

Lactation

The transfer to infants of arbutin/hydroquinone from uva ursi use during lactation has not been researched and therefore is not recommended; however, the risk remains speculative. It is recommended that this herb be used only in the lowest doses during lactation, observing the infant for side effects, and using under the guidance of a qualified health professional.

SAFETY INFORMATION: SIDE EFFECTS, CONTRAINDICATIONS, TOXICITY, AND HERB-DRUG INTERACTIONS

Used as per directed dose and duration, uva ursi appears to have a good safety profile.

Side Effects

• Nausea and vomiting have been reported with use, but are not common.

• Excessive ingestion of arbutin may cause tinnitus, delirium, convulsions, collapse, and death.

Contraindications

• Kidney disorders

• Pregnancy and lactation (discussed in the preceding)

• Children under 12 years old

• Bowel inflammation

No justification is given for the caution against use in children.

High tannin levels may interfere with iron absorption in the gut and may aggravate highly inflamed or ulcerated GI conditions.

Toxicity

Several authorities claim that arbutin-containing preparations should not be taken for longer than a consecutive week, nor should they be taken more than 5 times annually without medical consultation. No explanation for this recommendation is given though it is likely due to concern regarding hydroquinone consumption. Contrary to this, the European Scientific Cooperative on Phytotherapy (ESCOP) recommends treatment be continued until complete disappearance of symptoms, up to a maximum of 2 weeks. Uva ursi is a known inhibitor of melanin synthesis, and in excessive doses could result in retinal damage. Used acutely according to general dosing recommendations, this herb is expected to have very low carcinogenicity, though carci-nogenicity has been observed in mouse and rat models given pure hydroquinone.

Herb-Drug Interactions

• The only expected drug interaction is possible potentiation of prednisolone and related anti-inflammatory drugs by 50% methanolic extract.

 

 

Related posts:

1. USE IN PREGNANCY AND LACTATION Because of lack of clinical trials and safety data, SJW is not commonly recommended for the treatment of mood disorders during pregnancy. Its use is more often reserved for topical treatment of vaginitis, in the treatment of perineal tears, and for the treatment of sore, cracked nipples during lactation. It is becoming increasingly well established...
2. USE AND SAFETY IN PREGNANCY AND LACTATION Limited scientific literature is available on the safety of black cohosh during pregnancy and lactation, although it is traditionally used to ease labor. Black cohosh is generally contraindicated by most contemporary authors for use during pregnancy and lactation. The American Herbal Products Botanical Safety Handbook takes a slightly more liberal position and assigns black cohosh...
3. WILD YAM Botanical name: Dioscorea villosa Family name: Dioscoreacaea Synonyms: Colic root, rheumatism root Part used: Root and rhizome MAJOR CHEMICAL CONSTITUENTS Glycoside and steroidal saponins, including diosgenin and dioscin, alkaloids, tannins, phytosterols, and starch PRINCIPAL USES • Spasmolytic in the treatment of uterine cramping, dysmenorrhea, and chronic pelvic pain • Spasmolytic in cases of urinary tract...
4. GINGER Botanical name: Zingiber officinalis Family name: Zingiberacaea Part used: Rhizome MAJOR CHEMICAL CONSTITUENTS The major chemical constituents are volatile oils, including P-bisabolene and zingiberene, sesquiterpenes, including zingiberol, zingiberenol, the oleoresin shaogol, numerous monoterpene hydrocarbons, alcohols, and aldehydes, oleoresins, free fatty acids including palmitic acid, oleic acid, linoleic acid, caprylic acid, capric acid, lauric acid, myristic...
5. RED CLOVER Botanical name: Trifolium pratense Family name: Leguminosae Synonyms: Meadow clover, purple clover, trefoil Part used: Flowering tops and leaf MAJOR CHEMICAL CONSTITUENTS Isoflavondoids including biochanin A, daidzein, formo-nonetin, genistein, and others; flavonoids including kaempferol, quercetin and others; coumarins; carbohydrates, saponins, salicylic acid, and trace vitamins and minerals. PRINCIPAL USES • Prevention and treatment of menopausal...