Antioxidant activities of artichoke phenolics

Both leaves and heads from artichokes are rich in phenolic compounds belonging to different classes: benzoic and cinnamic derivatives, flavonoids and tannins. There are conditions when these phenolic compounds show antioxidant activities and quench different types of free radicals. Therefore, they can be used as nutrient compounds, because of their role in preventing and treating different diseases of radical origin, or as food preservatives. This research deals with the composition and biological activities of artichoke extracts prepared from leaves and heads. Mono-caffeoylquinic acids and di-caffeoylquinic acids are the predominant phenolics in these extracts, which also contain flavonoids (apigenin and luteolin glycosides) and tannins (hydrolysable and condensed tannins). Artichoke extracts and some of their pure phenolic constituents were assessed for their protective role in the control of oxidative damage to biological molecules (proteins, lipids and DNA), caused by free radicals such as RCOOo and/or OHo, and the mechanism of their action using the ?-carotene/linoleate assay, the deoxyribose assay and the metmyoglobin assay. The results of this study suggests that artichoke heads are rich in phenolics showing, in some conditions, a good antioxidant activity and might, therefore, be regarded as a source of dietary antioxidants. In addition, leaves and outer bracts of artichoke heads can be considered as a cheap, as yet unused, source of natural non toxic antioxidants for use in industrial processes (to preserve and stabilize the freshness, nutritive value, flavour and colour of foods).