Descrição
Ethnobotanical surveys conducted in Northeastern Portugal have documented the use of
Decoctions prepared with flowering aerial parts of Centaurea paniculata L. (starthistles,
knapweeds; port. escalabiosa) for inflammation and Helichrysum stoechas (L.) Moench (shrubby
everlasting; port. douradinha) for the respiratory system and to reduce fever [1], from the
Asteraceae botanical family. Although antioxidant properties of those plants have been
investigated [2-4], there are no reports on its most used form, the decoction. Therefore, in the
present work, decoctions of inflorescences and leafy flowering stems of the two mentioned
species were prepared and submitted to evaluation of antioxidant potential. Four different in vitro
assays were performed: scavenging effects on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals,
reducing power (measured in Folin Ciocalteu and ferricyanide Prussian blue assays), inhibition of
13-carotene bleaching and inhibition of lipid peroxidation in brain cell homogenates by TBARS
(thiobarbituric acid reactive substances) assay.
Thedecoction of H. stoechas revealed higher antioxidant activity (lower EC50 values) than C.
paniculata in all the tested assays. Data obtained could provide scientific evidence for some folk
uses in the treatment of diseases related to the production of reactive species and oxidative stress, but further experiments are required to explore the mechanisms of action.