Ferruginenes A−C from Rhododendron ferrugineum and Their Cytotoxic Evaluation

Funding

P.S. acknowledges the Austrian Federal Ministry for Science and research in the framework of ASEA UNINET for financial support during postdoctoral research within the program "technology Grants Southeast Asia". The authors wish to thank A. Russell and G. Cordt for their help with the collection of the plant material, J. Winkler (Department of Medicinal Chemistry, University of Vienna) for the optical rotation and CD measurements, J. Konig and M. Koberl (Department of Nutritional Sciences, University of Vienna) for facilitating the measurements of the HRESI mass spectra, and J. Gertsch (Institute of Biochemistry and Molecular Medicine, University of Bern) for the membrane receptor testing. We thank R. W. Doskotch (Division of Medicinal Chemistry and) Pharmacognosy, The Ohio State University) for kindly supplying the grayanotoxin derivatives. We also wish to thank M. Eisenbauer (Institute of Cancer Research, Medical University of Vienna) for kindly providing the HeLa-S3 cell lines and M. Anzelmo for preparing the extracts.