Phytochemical Content and Antioxidant Properties of Seeds of Unconventional Oil Plants

The lipophilic and hydrophilic antioxidants were evaluated in eight plants: safflower (Carthamus tinctorius), viper’s bugloss (Echium vulgare), quince (Cydonia vulgaris), evening primrose (Oenothera biennis), rose mosqueta (Rosa affinis rubiginosa), black seed (Nigella sativa), sea buckthorn (Hippophae rhamnoides) and borage (Borago officinales). The highest amounts of tocopherols were contained in seeds of borage and sea buckthorn (66.9 mg/100 g and 45.9 mg/100 g, respectively). The sea buckthorn seed lipids had the highest amount of total sterols (10.4 mg/g of lipids). The predominant form was campesterol. Sitosterol was the major sterol in the lipids of other tested seeds. The content of phenolic compounds ranged from 736.5 mg/100 g dry matter (d.m.) (evening primrose) to 74.8 mg/100 g d.m. (safflower). The highest antioxidant activity, expressed in % scavenged DPPH· free radicals, was observed for evening primrose (91.2%), while the lowest for safflower (36.2%). The correlation coefficient between the level of phenolic compounds and antioxidant activity was 0.53.