In vitro activity of 23 tea extractions and epigallocatechin gallate against Candida species
Author: Ming Chen and Lin Zhai and Maiken Cavling Arendrup
In this study, we investigate the susceptibility of Candida albicans, Candida glabrata, Candida krusei, Candida parapsilosis, Candida tropicalis, and Aspergillus fumigatus using the EUCAST microdilution minimum inhibitory concentration (MIC) method (final tea supernatant concentration range 5.0-0.005 mg/ml) to 23 different teas and tea catechins including epigallocatechin gallate (EGCG) isolated from green tea. All teas exhibited potent in vitro antifungal activity against C. glabrata. Six out of nine green teas and three of eight black teas had an MIC of 0.078 mg/ml, one white tea had an MIC of 0.156 mg/ml, and finally three of five oolong teas had an MIC of 0.156 mg/ml. Three teas exhibited activity against C. albicans (MIC 1.25 mg/ml), one green tea was active against C. parapsilosis (MIC 1.25 mg/ml), but none were effective against C. krusei, C. tropicalis or A. fumigatus at the concentrations tested. The MIC of EGCG was 0.3125 μg/ml against C. glabrata and 5.0 μg/ml against C. albicans and C. parapsilosis. The effect was fungicidal against C. glabrata at higher concentrations. In conclusion, EGCG and other yet undefined substances in tea have differential antifungal activity in vitro against C. glabrata, C. albicans and C. parapsilosis. These data indicate that components of tea and EGCG might be useful particularly for the treatment of C. glabrata infections and warrants further investigations.