Comparative study of in vitro methods used to analyse the activity of propolis extracts with different compositions against species of Candida.

Aims: Propolis is known for its activity against micro-organisms and different in vitro assays have been used to evaluate this activity, frequently with contradictory results.
Methods and Results: Brazilian propolis from the state of São Paulo was extracted by maceration using different concentrations of ethanol and water. The resultant extracts were analysed by chromatographic methods. Several microbiological methods were compared to determine which one best evaluated the activity of the propolis extracts against species of Candida, with average minimal inhibitory concentration values between 6 and 12 mg ml(-1).
Conclusions: Agar dilution in plates showed the clearest results. These were in agreement with the chromatographic analyses, which also identified the active substances.
Significance and Impact of the Study: Although the active substances identified in this sample are typical of Brazilian propolis, their activity against Candida had not been recognized previously, demonstrating the importance of standardizing the correct combination of microbiological and chromatographic analyses.