Antimicrobial activity of berberine--a constituent of Mahonia aquifolium.

The antimicrobial activity of the protoberberine alkaloid, berberine, isolated from Mahonia aquifolium, was evaluated against 17 microorganisms including two Gram-negative bacteria--Pseudomonas aeruginosa and Escherichia coli (both resistant and sensitive), two Gram-positive bacteria--Bacillus subtilis and Staphylococcus aureus, Zoogloea ramigera, six filamentous fungi--Penicilium chrysogenum, Aspergillus niger, Aureobasidium pullulans (black and white strain), Trichoderma viride (original green strain and brown mutant), Fusarium nivale, Mycrosporum gypseum and two yeasts--Candida albicans and Saccharomyces cerevisiae. The IC50, minimum inhibitory concentration (MIC), minimum microbicidal concentration (MMC) and minimum microbistatic concentration (MMS) varied considerably depending on the microorganism tested, the sensitivity decreasing as follows: S. aureus > P. aeruginosa S (sensitive) > E. coli S > P. aeruginosa R (resistant) > E. coli R > B. subtilis > Z. ramigera > C. albicans > S. cerevisiae > A. pullulans B (black) > A. pullulans W (white) > T. viride Br (brown) > M. gypseum > A. niger > F. nivale > P. chrysogenum > T. viride G (green).