Phenolic profile, tocopherols and antioxidante activity of watercress
Artigo de Conferência
Visão geral
Visão geral
resumo
Watercress (Nasturtium officinale R. Br.) is a cruciferous vegetable of the Brassicaceae famity
frequently classed as superfood. Several epidemiological studies have established a positive
correlation between its consumption and a reduced risk of chronic diseases such as diabetes,
cardiovascular diseases and câncer [1, 2]. These health-promoting effects can be attributed to
antioxidant nutrients (such as tocopherols) and non-nutrients (such as phenolic compounds), which
may act synergistically and offer protection against oxidative stress and degenerative diseases. This
study was carried out aiming to characterize the watercress profile in phenolic compounds and
tocopherols and evaluate its antioxidant properties. Wild specimens of watercress were collected in a
stream located in the munidpality of Bragança, Portugal, and promptly analyzed. Phenolic
compounds were analyzed by HPLC-DAD-ESI/MS and tocopherols by HPLC with a fluorescence
detector [3, 4]. Hydroalcoholic extracta were prepared by solid-liquid extraction and four in vitro assays
were performed to evaluate the antioxidant capacity, which was assessed via DPPH free-radical
scavenging activity, reducing power (ferricyanide/Prussian blue assay), p-carotene bleaching
inhibition (p-carotene-linoleate model system), and thiobarbituric acid reactive substances (TBARS)
formation inhibition in brain homogenates [3,4]. Watercress was particularly rich in flavonoids, mainly
quercetin and isorhamnetin derivatives. Interesting amounts of hydroxycinnamic acids were also
detected. a-Tocopherol was identified as the predominant isoform, followed by y- and p-tocopherols.
The low ECso values for the TBARS formation and p-carotene bleaching inhibition revealed that the
hydroalcoholic extracts have a high lipid peroxidation inhibition capacity. These results support the
consumption of watercress as source of phytochemicals potentially capable of inhibiting free radicalmediated
reactions and its dassification as a superfood.
