Food antioxidants and phytochemicals: present and future perspectives

The relatively high concentration of phenolic flavonoids in nines, grapes, green tea, and berry extracts contributes powerful antioxidant properties t hat may be beneficial by reducing oxidative reactions deleterious to health . Our data showed that polyphenolic compounds in red wine and grapes strong ly inhibit the oxidation of human low-density lipoproteins (LDL), a reactio n that initiates atherosclerosis and heart diseases. Marked variations were found in antioxidant activity of rosemary, green tea, and berry extracts i n different lipid systems. These variations are attributed to differences i n partition between phases in various lipid systems. The activities of natu ral antioxidants are thus very system dependent and their effectiveness in different real food systems is difficult to predict. In addition to prevent ing LDL oxidation, plant flavonoids may reduce the thrombotic tendencies an d inflammatory reactions in the body. Thr antioxidant activity of phenolic compounds in wine, grapes, green tea, and berry extracts supports the epide miological evidence that fruits and vegetables may have a cardioprotective effect. More research is needed however to relate the extensive in vitro st udies showing the potent antioxidant activities of flavonoids to their pote ntial health effects in the dirt.