Glucosinolates, β-thioglucoside-N-hydroxysulfates with variable side chains are secondary metabolites that are synthesized from amino acids. They were found in 16 families of Capparales. These compounds particularly belong to Brassicaceae family, which includes the most plants of everyday nutrition such as broccoli, cabbage, cauliflower, turnip, radish and others. These compounds are chemically stable and biologically inactive. Damage to the tissue results in contact between the enzymes myrosinase and glucosinolates leading to their hydrolysis which creates a variety of biologically active breakdown products. In this diploma thesis, two plant species were studied Diplotaxis tenuifolia (L.) DC. and Matthiola incana (L.) R.Br. The aim of the study was to investigate the glucosinolate profile in various parts of D. tenuifolia and M. incana. Glucosinolates were identified by GC-MS analysis of their breakdown products and HPLC-DAD- MS/MS by analyzing desulfated glucosinolates. The same were quantified in different parts of plants according to the official ISO 9167-1 method based on the HPLC analysis of desulphoglucosinolates. Glucosinolates glucoerucin (5.62-15.85 μmol/g) and glucoraphanin (0.63-2.83μmol/g) were identified in all plant parts of D. tenuifolia (seed, leaf, stem, flower) identified. In all plant parts of M. incana (mussel, leaf, stem, flower), glucoraphenin (1.53-21.03 μmol/g) and glucoraphanin (tr-0.08 μmol/g) were identified, while indole glucosinolate glucobrassicin was confirmed in flower (0.39 μmol/g). In this study, the thermal decomposition of the glucosinolates of the D. tenuifolia plant was investigated using various isolation methods: hydrodistillation in a modified apparatus by Clevenger (100 ° C, 150 min) and distillation and extraction with microwaves (500 W, 98 ° C, 35 min). Volatile compounds analyzed by GC-MS indicate that the main glucosinolate glucoerucine is differently dissociated. 4- (methylsulfanyl) butyl isothiocyanate was the main product obtained by hydrodestillation, while 5- (methylsulfanyl) pentanonitrile was a dominant breakdown product obtained by micro-assisted isolation .