Antifungal activity of Mahonia aquifolium extract and its major protoberberine alkaloids.

The crude extract of Mahonia aquifolium (Berberidaceae) stem bark and its components berberine, palmatine and jatrorrhizine were screened for their inhibitory activity against a variety of dermatophytes and two Candida species of human origin using the in vitro dilution agar plate method. Jatrorrhizine was found to be the most effective against all fungal species tested (MIC ranges from 62.5 to 125 micro g/mL), while the crude extract, berberine, and palmatine exhibited only marginal activity (MIC 500 to >/= 1000 micro g/mL). Dermatophytes were more susceptible to jatrorrhizine than yeasts, and Scopulariopsis brevicaulis appeared the least sensitive species to all the compounds tested. The effects of the alkaloids were compared with those of fluconazole and bifonazole for which the MIC ranges were 12.5 to >100 micro g/mL. Our results suggest that jatrorrhizine may serve as a leading compound for further studies to develop new antifungal agents with highly potent antifungal activity and low host toxicity.