1. Department of Organic Chemistry, University of Debrecen, P.O. Box 400, H-4002 Debrecen, Hungary
2. Department of Biochemistry and Biotechnology, University of Thessaly, Biopolis, 41500 Larissa, Greece
3. Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary
4. Institute of Biology, Pharmaceutical Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece