Abstract

Polyphenols and particularly flavonoids are widely appreciated for their potential beneficial health effects, like antioxidant or anticarcinogenic activities. The aim of this study was to determine the antioxidant activity of extracts of some shrubs that grow spontaneously in Portugal (Pterospartum tridentatum, Cytisus scoparius and Erica spp.) and then to correlate it with total phenolic and flavonoid compounds. The Folin-C method was used to determine total phenols while a colorimetric method with aluminum chloride was used for the determination of total flavonoids. Regarding the determination of antioxidant activity, two distinct methods (DPPH assay and beta-carotene bleaching test) were used. It was concluded that all the extracts presented relevant antioxidant activity and there was a positive linear correlation between antioxidant activity index and total phenolic content.

Key words: Vegetal extracts, phenolics, flavonoids, antioxidant activity.