Psoriasis is a common skin disorder that affects more than 4.5 million people in North America. Treatment of psoriasis is problematic because the severity and distribution of psoriatic plaques varies immensely. Localized psoriasis can often respond to topical medications, of which steroid and vitamin D analogue creams such as calcipotriol, anthralin, coal tar, and ultraviolet light treatments are the most common.More generalized involvement of the skin may require systemic treatments with retinoids, immunosuppressives, PUVA, or biologic medications.
M. aquifolium (Barberry, Oregon grape, Berberis) belongs to the berberidaceae family and grows wild in Europe, North and South America. M. aquifolium was initially used in American folk medicine as an oral medication for inflammatory skin diseases, including psoriasis and syphilis. The root and wood of M. aquifolium contain many isoquinoline alkaloids, of which berberine is the best characterized. The mechanism of action of the alkaloids in suppressing the inflammatory response is poorly understood; however, laboratory studies have suggested that the alkaloids may inhibit DNA synthesis by blocking reverse transcriptase, inhibit lipoxygenase and lipid peroxidation, and/or inhibit the cyclooxygenase-2 pathway through the reduction of prostaglandin E2. Topical application of M. aquifolium has been shown by immunohistochemistry to reduce the inflammatory and keratinocyte hyperproliferation markers typical of psoriasis. Several open and placebo-controlled clinical trials have supported the effectiveness of M. aquifolium in the treatment of psoriasis. In these trials, between 70% and 81% of patients improved on the basis of physician and patient assessment. Adverse events upon application of M. aquifolium ointment included burning and itching sensations.