Xanthones from roots, hairy roots and cell suspension cultures of selected Hypericum species and their antifungal activity against Candida albicans.

CONCLUSIONS

Highest xanthone contents were found in Hypericum pulchrum and H. annulatum untransformed roots. The best anti- Candida activity was obtained for hairy roots extracts of H. tetrapterum clone 2 ATCC 15834. Extracts of root cultures, hairy roots and cell suspensions of selected Hypericum spp. were screened for the presence of xanthones and tested for their antifungal activity against Candida albicans strain ATCC 10231. At least one of the following xanthones, 5-methoxy-2-deprenylrheediaxanthone; 1,3,6,7-tetrahydroxyxanthone; 1,3,5,6-tetrahydroxyxanthone; paxanthone; kielcorin or mangiferin was identified in methanolic extracts of the untransformed root cultures. The highest total xanthone content, with five xanthones, was found in untransformed H. pulchrum and H. annulatum root cultures. Hairy roots and the controls of H. tetrapterum contained 1,7-dihydroxyxanthone, while hairy root cultures and the corresponding controls of H. tomentosum contained toxyloxanthone B, 1,3,6,7- and 1,3,5,6-tetrahydroxyxanthone. Two xanthones, cadensin G and paxanthone, were identified in cell suspension cultures of H. perforatum. Their content increased about two-fold following elicitation with salicylic acid. The anti-Candida activity of the obtained extracts ranged from MIC 64 to >256 µg ml(-1). Among the extracts of Hypericum untransformed roots, the best antifungal activity was obtained for extracts of H. annulatum grown under CD conditions. Extracts of hairy roots clones A4 and 7 ATCC15834 of H. tomentosum and clone 2 ATCC15834 of H. tetrapterum displayed inhibition of 90% of Candida growth with 256 μg ml(-1). Extracts from chitosan-elicitated cells did not show antifungal activity.