The antioxidant activities of methanol and ethyl ether extracts obtained from Thymus zygis, collected during the flowering or non-flowering period, were evaluated and compared. To investigate this potential, extracts were tested on their capacity to react with diphenyl-picrylhydrazyl (DPPH) in a homogeneous medium, and to inhibit Fe²⁺/ascorbate-induced membrane lipid peroxidation, as estimated by the formation of thiobar-bituric acid-reactive substances (TBARS). Although methanol extracts reduce DPPH radicals more efficiently than ethyl ether extracts, suggesting a potent radical scavenger activity, the ethyl ether extracts were found to be most active in inhibiting lipid peroxidation in sarcoplasmic reticulum (SR) membranes. In addition, both extracts present peroxyl and superoxide radical scavenging activities. Peroxyl radicals were generated by the water soluble 2, 2A-azobis(2-amidinopropane) dihydrochloride (AAPH) azoinitiator, and the scavenging activities of the extracts were measured by the inhibition of cis-parinaric acid (PnA) fluorescence decay in SR. Superoxide radicals were generated either by an enzymatic or a non-enzymatic system, and the scavenger ability was evaluated by the inhibition of nitrob-lue tetrazolium reduction. Methanolic extracts are more potent as scavengers of peroxyl and super oxide radicals than the ethyl ether extracts. Apparently, there is a relationship between antioxidant potency and the total phenolic groups content in each extract.

The potential use of polyphenols in the prevention and treatment of chronic inflammatory diseases has been extensively investigated although the mechanisms involved in cellular signaling need to be further elucidated. Cyanidin-3-glucoside is a typical anthocyanin of many pigmented fruits and vegetables widespread in the human diet. In the present study, the protection afforded by cyanidin-3-glucoside against cytokine-triggered inflammatory response was evaluated in the human intestinal HT-29 cell line, in comparison with 5-aminosalicylic acid, a well-established anti-inflammatory drug, used in inflammatory bowel disease. For this purpose, some key inflammatory mediators and inflammatory enzymes were examined. Our data showed that cyanidin-3-glucoside reduced cytokine-induced inflammation in intestinal cells, in terms of NO, PGE₂ and IL-8 production and of iNOS and COX-2 expressions, at a much lower concentration than 5-aminosalicylic acid, suggesting a higher anti-inflammatory efficiency. Interestingly, cyanidin-3-glucoside and 5-aminosalicylic acid neither prevented IkB-α degradation nor the activation of NF-kB, but significantly reduced cytokine-induced levels of activated STAT1 accumulated in the cell nucleus. In addition, we established that phosphorylated p38 MAPK was not involved in the protective effect of cyanidin-3-glucoside or 5-aminosalicylic acid. Taking into account the high concentrations of dietary anthocyanins potentially reached in the gastrointestinal tract, cyanidin-3-glucoside may be envisaged as a promising nutraceutical giving complementary benefits in the context of inflammatory bowel disease.