Oregon GrapeMahonia aquifolium, Berberis aquifolium
The roots and bark of the shrub Mahonia aquifolium (also called Oregon grape) have traditionally been used both orally and topically to treat skin problems. They were also used for other conditions such as gastritis, fever, hemorrhage, jaundice, gall bladder disease, and cancer. In addition, Mahonia was used as a bitter tonic to improve appetite.
According to some experts,
is identical to the plant named
, but others point to small distinctions.
, commonly called
What Is Oregon Grape Used for Today?
Oregon grape is primarily used today as a topical treatment for psoriasis
Oregon grape has been proposed as a treatment for other skin diseases, such as fungal infections (such as
Many studies have been performed on purified berberine, a major chemical constituent of Oregon grape and other herbs such as goldenseal, but it is not clear whether their results apply to the whole herb. In addition, impossibly high dosages of the herb would be required to duplicate the amount of berberine used in many of these studies. (For more information, see the article on
What Is the Scientific Evidence for Oregon Grape?
Evidence from two double-blind, placebo-controlled
In a double-blind study published in 2006, two hundred people were given either a cream containing 10% Oregon grape extract or placebo twice a day for 3 months.
Benefits were also seen in a double-blind, placebo-controlled study of 82 people with psoriasis.
Another study found that dithranol, a conventional drug used to treat psoriasis symptoms, was more effective than Oregon grape.
Laboratory research suggests Oregon grape has some effects at the cellular level that might be helpful in psoriasis, such as slowing the rate of abnormal cell growth and reducing inflammation.
Topical ointments or creams containing 10% Oregon grape extract are generally applied 3 times daily to the affected areas.
Oregon grape appears to be safe when used as directed. In the large open study described above, only 5 of the 443 participants reported side effects of burning, redness, and itching. 12
However, because Oregon grape contains berberine, which has been reported to cause uterine contractions and to increase levels of bilirubin, oral consumption of Oregon grape should be avoided by pregnant women.
There is an additional concern regarding the berberine content of Oregon grape. One study found that berberine impairs metabolism of the drug cyclosporine, thereby raising its levels.
3. Augustin M, Andrees U, Grimme H, et al. Effects of Mahonia aquifolium ointment on the expression of adhesion, proliferation, and activation markers in the skin of patients with psoriasis. Forsch Komplementrmed. 1999;6(suppl 2):19-21.
8. Augustin M, Andrees U, Grimme H, et al. Effects of Mahonia aquifolium ointment on the expression of adhesion, proliferation, and activation markers in the skin of patients with psoriasis. Forsch Komplementrmed. 1999;6(suppl 2):19-21.
16. Wu X, Li Q, Xin H et al. Effects of berberine on the blood concentration of cyclosporin A in renal transplanted recipients: clinical and pharmacokinetic study. Eur J Clin Pharmacol. 2005 Aug 26. [Epub ahead of print]
17. Klovekorn W, Tepe A, Danesch U. A randomized, double-blind, vehicle-controlled, half-side comparison with a herbal ointment containing Mahonia aquifolium , Viola tricolor , and Centella asiatica for the treatment of mild-to-moderate atopic dermatitis. Int J Clin Pharmacol Ther. 2007;45:583-591.
Last reviewed April 2009 by EBSCO CAM Review Board
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