In this thesis the antioxidant activity, total polyphenol and total antocyanin in different species from order Solanales was determined. White-, red-, blue-fleshed potato and white-, orange-fleshed sweet potato was analyzed. Extraction of the polyphenols from potato was performed by ultrasonication with methanol/HCl = 99/1 (v/v). For determination content of total polyphenol and total antocyanin were characerized by Folin Ciocalteu assay. Larger amount of total polyphenols were present in blue-fleshed potato (92,69 mg GAE / 100 g FW) and in white-fleshed potato was determined lowest amounts od total polyphenols (30,34 GAE / 100 g FW). In white- and orange-fleshed sweet potato was present in amounts of 79,49 GAE / 100 g FW for white-fleshed and 72,33 GAE / 100 g FW orange-fleshed sweet potato. Anthocyanins was measured using the pH differential method and total antioxidant capacity was expressed in cyanidin-3-glucoside equivalents. Anthocyanins was determined only in red- and blue-fleshed potato in amounts od 26,57 and 6,77 mg Cyd-3-glu / 100 g FW. The antiradical activity of different fractions was determined using the DPPH method and was eypressed in Trolox equivalents (TEAC) / kg FW. TEAC valutes vary from the higest valutes for the orange-fleshed sweet potato (8.43 mmol TE / kg FW), to the lowest valutes for the blue-fleshed potato (6,73 mmol TE / kg FW). The expected coleration between amounts od total polyphenols and antioxidant capacity was`t found.