1. Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. Georgi Bonchev Str., bl. 9, 1113 Sofia, Bulgaria
2. Department of Food and Drug, University of Parma, Parco Area delle Scienze 47/A, 43124 Parma, Italy
3. Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy