Estudo do potencial antioxidante de vegetais da família cruciferae de diferentes cultivos
Arbos, Kettelin Aparecida
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Abstract: Free radicals are formed throughout cellular metabolism. As fairly unstable and highly reactive substances, they are able to cause oxidation and sometimesirreversible damage to the cells, compromising their function. Although produced at high levels, most of them can be inactivated by antioxidants. The Cruciferae family has many species that are important for the regular human diet, as they provide important antioxidant components such as vitamins, minerals, fibers, flavonoids, carotenoids amongst others phytochemicals. As such, it is important to evaluate their antioxidant potential as they are routinely present as part of the Brazilian folk meals. In the present work, the antioxidant capability of the extracts prepared from white cabbage (Brassica oleracea var. capitata L.j, kale (Brassica oleracea L. var. acephala D.C.J, cauliflower (Brassica oleracea L. var. botrytis L. subv. cauliflora), broccoli (Brassica oleracea L. var. botrytis L. subv. cymosa), water-cress (Nasturtium officinalis L.) and radish (Raphanus sativus radiculal L.J, obtained from conventional, hydroponics, and organic agricultural procedures whereas possible, was investigated in vitro by the chemical methods of phosphomolybdenum complex and DPPH. In parallel, we have developed an in vitro biological assay for investigating the antioxidant potential of the kale and broccoli extracts using normal human erythrocytes under oxidative stress imposed by phenylhydrazine as an experimental model, in which the methemoglobin levels were measured. The influence of chlorophyll and lipophilic components (C/LS) on the antioxidant properties of these extracts was also studied. Although the intensity of the effects varied according to the species and dose investigated, their way of growing, and the methodological approach used, all Cruciferae extracts included in this work have shown significant antioxidant capacity when compared to the controls. The absence of C/LS resulted in the enhancement of the extracts' antioxidant potential, independently of the type of culture, but it reached significant levels only for the extracts prepared from the conventional agriculture. Of particular interest were the results derived from the biological method proposed that have shown to be sensitive, fast, reproducible, and economically feasible. Although the antioxidant results herein presented and discussed must be interpreted with caution as a list of factors such as soil composition, climate or culture technology can influence the vegetables' quality, they favor the beneficial effects of consuming Cruciferae vegetables, particularly those obtained from organic culture, including their advantage of having less fertilizer and toxic residues associated with high levels of solid nutrients.
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