Antioxidant potential of ragweeds: Ambrosia artemisiifolia, A. trifida and Iva xanthifolia

The purpose of this study was to analyze antioxidant systems among three invasive ragweed species, Ambrosia artemisiifolia L., A. trifida L. and Iva xanthifolia Nutt. Antioxidant capacity could be a possible marker of adaptation to variable environmen?tal conditions, since change in amount of antioxidants represents one of the first responses to various environmental stimuli. Among investigated ragweeds, I. xanthifolia leaves had more pronounced guaiacol peroxidase activity (87.5 and 62.5%) and reduced glutathione content (2.3 and 28.8%) than A. artemisiifolia and A. trifida, respectively. However, super?oxide dismutase activity was invariable in all investigated plants (234.1-247.5 U g-1 fresh weight). The highest content of total phenolics, tannins, flavonoids and proanthocyanidins were detected in A. trifida leaves (up to 3.7 - fold the amount of the others). According to antioxidant activity tests, investigated ragweed species could be presented in a scale: A. trifida > I. xanthifolia > A. artemisiifolia. Accumulation of non-enzymatic antioxidants and lower content of reduced glutathione point to different oxidative stress avoidance strategies of A. trifida when compared to A. artemisiifolia and I. xanthifolia within the same environ?mental conditions.