Enhanced antifungal activity of ketoconazole by Euphorbia characias latex against Candida albicans

The in vitro suseptibility of Candida albicans to ketoconazole and Euphorbia characias latex alone or in combination was tested using the macrobroth dilution method. The MIC 80% of crude latex and ketoconazole are respectively 159 mug protein/ml and 0.3901 mug/ml. This method permits us to determine an affinity constant K-aff for crude latex (0.015 mug(-1) protein ml) and ketoconazole (23.828 mug(-1) ml). The utilization of a mixture of latex at several concentrations (7.8-15.62-31.25-62.5 and 125 tg protein/ml) and ketoconazole indicates a synergistic effect between latex and ketoconazole. For latex concentrations of 31.25 and 62.5 mug protein/ml the MIC 80% of ketoconazole were inferior (0.194 and 0.183 mug/ml respectively) to that obtained with ketoconazole alone (0.390 mug/ml). A synergistic effect is therefore obtained between ketoconazole on the one hand and two concentrations of Euphorbia characias latex. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.