Mahonia nervosa

Mahonia nervosa contains berberine, its primary active alkaloid, which exerts antimicrobial and anti-inflammatory effects. Berberine inhibits bacterial enzyme function and disrupts cell membrane integrity in pathogenic organisms. The plant's tannins provide astringent properties that help tone and protect irritated skin tissue, while berbamine contributes additional antimicrobial activity. These combined actions explain its traditional use by Pacific Northwest tribes for skin diseases and wound healing. Evidence Level: C (preclinical and traditional use support).

Mahonia nervosa may interact with medications metabolized by cytochrome P450 enzymes due to its berberine content. Berberine can inhibit CYP3A4, CYP2D6, and CYP2C9, potentially increasing blood levels of drugs like cyclosporine, certain antidepressants, and some antibiotics. It may also enhance the effects of antidiabetic medications and blood thinners. Those taking prescription medications should consult a healthcare provider before using Mahonia nervosa. Evidence Level: C.

The standard adult dosage for Mahonia nervosa tincture is 2-4 mL taken three times daily, which translates to approximately 40-80 drops per dose. The tincture is typically prepared from the root or bark. For external skin applications, the tincture may be diluted and applied topically. Always follow manufacturer instructions or consult a qualified herbalist, as individual needs may vary based on the condition being addressed. Evidence Level: Traditional.

Mahonia nervosa is contraindicated during pregnancy and breastfeeding. The berberine content can cross the placenta and has been associated with neonatal jaundice. Berberine may also stimulate uterine contractions and pass into breast milk, potentially affecting nursing infants. Pacific Northwest tribes traditionally avoided this herb during pregnancy. Women who are pregnant, planning to become pregnant, or breastfeeding should avoid Mahonia nervosa entirely. Evidence Level: C (based on berberine safety data).

Mahonia nervosa has been used traditionally by Pacific Northwest Native American tribes, including the Lummi people, for liver support, digestive complaints, and skin conditions. The root and bark were prepared as decoctions or applied topically for wounds, rashes, and skin diseases. Modern herbalists use it similarly for its antimicrobial and hepatoprotective properties. It may support liver function and help address certain skin conditions, though clinical evidence remains limited. Evidence Level: C.

Mahonia nervosa may cause mild gastrointestinal effects including nausea, diarrhea, and stomach discomfort, particularly at higher doses. The berberine content can cause neonatal jaundice in infants exposed during pregnancy or through breast milk. Some individuals may experience allergic skin reactions with topical application. Long-term use may affect liver enzyme function. Discontinue use if adverse effects occur and consult a healthcare provider. Evidence Level: C.