Action of helenin on microorganisms

The action of helenin on 10 genera of bacteria and yeasts and on 8 genera of dermatophytes was studied. The minimal inhibitory concentration for gram-positive bacteria ranged from 10 to 400 mug/ml, for gram-negative bacteria from 100 to 800 mug/ml, for yeasts from 200 to 750 mug/ml, and for dermatophytes from 50 to 500 mug/ml. Strains naturally resistant to helenin are very rare.