There is increasing evidence that by altering the redox-mediated cell pathways leading to the activation of transcription factors that control the expression of a number of mediators, reactive oxygen species (ROS) play a key role in promoting the inflammatory process. Such undesired effects of oxidative stress have been found to be counteracted by the activity of various dietary phytochemicals, non-nutritive secondary metabolites which provide plants with colours, flavour and natural toxicity to pests. The large majority of these compounds are polyphenolic substances such as flavonoids, with well known radical-scavenging and antioxidant properties. More recent data showed that other non-polyphenol compounds may be considered. Among these, the betalain indicaxanthin and betanin, the characteristic pigments of the cactus pear fruit (Opuntia Ficus Indica), have been investigated for their radical-scavenging properties in a number of in vitro models, either chemical or biological. Lack of toxicity and high bioavailability add further interest to these molecules. With this background this study will investigate the effects of the two betalains on an inflammation model that includes cultured macrophages under inflammatory stimuli by lipopolysaccharide (LPS). The activation of nuclear factor kB, and the levels of various markers of the inflammatory response (iNOS, COX2, nitrites, and PGE2) will be assessed.
An inflammatory process has to be regarded as an important causative event in a number of chronic and degenerative conditions including cancer and cardiovascular diseases. Prevention and/or treatment with natural antioxidants of plant origin may be an effective alternative for these diseases. Our findings may contribute new insights to the well-known health-promoting activity of fruit and vegetables, and suggest novel strategies in developing phytochemical functional products. In addition they may help to characterize the Sicilian cactus pear fruit as a "functional food". METODOLOGIE Indicaxanthin and betanin will be isolated from cactus pear (Opuntia ficus-indica) fruits (red and yellow cultivar) by methanolic extraction, and purified by liquid chromatography on Sephadex G-25, followed by semi-preparative reversed-phase HPLC. RAW 264.7 cells cultured in DMEM medium, will be seeded in density of 0.25 x 106 cells/ml and treated with LPS (1 microg/ml), either in the absence, or in the presence of 1-20 microM betalains for 16 h at 37 °C in a CO2 incubator. The expression of iNOS and COX-2 will be evaluated by immunoblotting and Real Time-PCR. Nitrites and PGE2 levels, in the culture medium, will be measured by Giemsa reagent and EIA, respectively. Influence of the two betalains on the LPS-mediated NF-kB activation, will be investigated by the NF-kB luciferase report assay.
|Data di inizio/fine effettiva||1/1/06 → …|
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