[1] Med Univ Plovdiv, Fac Pharm, Dept Bioorgan Chem, Plovdiv 4002, Bulgaria
[2] Med Univ Plovdiv, Fac Pharm, Dept Med Phys & Biophys, Plovdiv 4002, Bulgaria
[3] Med Univ, Fac Pharm, Dept Pharmacol Pharmacotherapy & Toxicol, Lab Expt Chemotherapy, Sofia 1431, Bulgaria
[4] Univ Food Technol, Technol Fac, Dept Microbiol, Plovdiv 4002, Bulgaria
[5] Med Univ Sofia, Fac Pharm, Dept Pharmacognosy, Sofia 1000, Bulgaria
[6] Med Univ Sofia, Fac Pharm, Dept Chem, 2 Dunav Str, Sofia 1000, Bulgaria
[7] Paisij Hilendarski Univ Plovdiv, Fac Chem, Dept Organ Chem, Plovdiv 4000, Bulgaria