Isolation of antioxidant components from Cichorium intybus

Free radicals have been implicated in aging and a number of chronic diseases such as cardiovascular diseases, cancer and inflammatory processes. Recent reports indicate that reactive oxygen and nitrogen substance (ROS-RNS) are also involved in neurological disorders including Alzheimer's disease, one of the most frequent causes of dementia in the aged. Epidemiological studies have indicated clear relations betwen diet and cancer and coronary heart disease. The consumption of vegetables and fruits have protective effects against various forms of neoplastic and heart diseases. The principal agents responsible for the protective effects are vitamins A, C, and beta-carotene because of their antioxidant and antiradical properties. In recent years it has become apparent that other dietary components, in particular phenols which are ubiquitous in plants, can strongly contribute to the positive effects of vegetable foods. We tested the antioxidant properties of six cicoriaceae commonly used in the mediterranean diet. The antioxidant activity was determined on vegetable juices obtained by simple centrifugation and filtration at 2°C, to minimize the effects of handling. The antioxidant activity (AA) was determined in vitro using a model system containing beta-carotene-linoleic acid, and ex vivo as protective activity (PA) against rat liver microsome lipid peroxidation induced by xenobiotic (CCl4) and measured by malondialdehyde release. Among the examined species, Cichorium intybus was the most active, its juice efficiently suppressing lipid peroxidation induced in vitro and ex vivo. We thus continued our research in order to isolate antioxidant components. Steric exclusion chromatography (SEC) minimizes the interactions with the analyte, gives a good indication about its molecular size and furthermore allows us to obtain enough juice components to carry out the biological assay. The dark brown juice was fractionated using Toyopearl HW 40F resin (exclusion limits 100-10000Da). We obtained four fractions and only that with higher MW showed antioxidant and protective activity, while the other fractions were pro-oxidant. The vegetable juice was then submitted to dialysis using cellulose membrane (molecular weight cut off 30000) which confirmed the high molecular size of the active compounds. We propose to separate and characterize these components.