1. Institute of Chemical Engineering, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
2. Department of Pharmacognosy, Faculty of Pharmacy, Medical University, 1000 Sofia, Bulgaria
3. Department of Dendrology, University of Forestry, 1756 Sofia, Bulgaria
4. Department of Pharmaceutical Botany, Faculty of Pharmacy, Medical University of Lublin, 20-059 Lublin, Poland