Arctostaphylos uva- ursi

Arctostaphylos uva- ursi                        

Common name:  Bearberry, Uva ursi, Kinnikinnick

Family: Ericaceae

Parts used: Leaves

Constituents: 

• Hydroquinone glycosides (arbutin)
• Tannins (Hydrolyzable & Condensed)
• Flavonoids
• Polyphenolic acids (ursolic, gallic & ellagic)
• Allantoin
• Volatile oil

Medicinal actions:

• Anti-inflammatory
• Antimicrobial (tissue specificity to urinary tract)
• Astringent
• Demulcent
• Diuretic

Medicinal use:

• Is used primarily as a diuretic in the treatment of cystitis and to soothe and tonify the urinary organs, as it will remove excess water from the body.
• Considered to impart tone, induce normal contraction of the bladder, and restrain excessive mucous discharges.
• Is frequently used with stones or ulceration in either the kidney or the bladder, or as part of a holistic approach to chronic kidney problems.
• Exerts a soothing influence on the genitourinary tract as a whole.

Pharmacology:

• Hydroquinone derivative, arbutin appears to release aglycone in alkaline urine leading to antimicrobial effects. Arbutin, which is cleaved and conjugated to form hydroquinones, is a known inhibitor of tyrosine kinase and thus melanin synthesis, used in skin whitening treatments.
• Tannins are highly astringent.
• Allantoin helps promote the growth of healthy new cells and the healing of wounds.
• Note: The whole plant is more effective than isolated arbutin, which may be related to the activity of flavonoids (gallic acid or gallotannin) which prevents the splitting of arbutin by such enzymes as b-glucosidase. This enzyme is present in some enteric microorganisms that can occur in urinary tract infections.  Thus, the flavonoid component allows more arbutin to be hydrolyzed than when isolated arbutin is administered.

Pharmacy: 

• Infusion: 1 tbsp (3 g)/cup water, TID.
• Tincture: (1:2, 40%), 4-8 ml QD, 60 ml weekly max.
• Capsules: 3-12 g QD (equivalent to 400-840 mg arbutin), or 500 mg DHE, TID.
• Note: Pulse dosing required (2 weeks max). 

Toxicity: 

• Toxicity is proportional to the conversion of arbutin to hyrdroquinone, as hydroquinone is mutagenic. 15 g of the fresh leaves can provide 1 g of hydroquinone, which can be toxic with signs and symptoms of: tinnitus, nausea, vomiting, shortness of breath, cyanosis, convulsions, and delirium.
• Caution due to hydrolyzable tannin content that can accumulate, causing liver and kidney damage.

Contraindications:

• Avoid during pregnancy & lactation, renal failure, and long-term use ( > 14 days).

Interactions: 

• High doses of vitamin C and cranberry juice will transiently acidify the urine in a minority of people. Considering that arbutin may convert preferentially to hydroquinone in alkaline urine, urinary acidifiers can theoretically inhibit this conversion.
• High tannins may interfere with absorption of various nutrients (e.g iron).

References:

• Find a complete list of references for this monograph as well as images and a review of its evidence based applications in Dr. Marciano’s Herbal Textbook.