1. University of Chemistry and Technology in Prague, Faculty of Food and Biochemical Technology; Department of Chemistry of Natural Compounds; Technická 5 16628 Prague 6 Czech Republic
2. Institute of Experimental Botany, Academy of Sciences of the Czech Republic; Isotope Laboratory; Vídeňská 1083 14220 Prague 4 Czech Republic
3. University of Chemistry and Technology in Prague, Faculty of Food and Biochemical Technology; Department of Biochemistry and Microbiology; Technická 5 16628 Prague 6 Czech Republic