1. Department of Organic Chemistry, University of Debrecen, POB 400, H-4002 Debrecen, Hungary
2. Department of Agricultural Botany, Crop Physiology and Biotechnology, University of Debrecen, Böszörményi út 138, H-4032 Debrecen, Hungary
3. Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary