Abstract

The present study was conducted to assess the antioxidant activity of Hypericum species endemic to South Brazil, H. caprifoliatum, H. carinatum, H. myrianthum and H. polyanthemum. The free radical scavenging properties of plant extracts were evaluated employing different methodologies, including the bleaching of a stable free radical (2,2-diphenyl-l-picrylhydrazyl, DPPH) and the peroxyl reactivity indexes TRAP (Total Reactive Antioxidant Potential) and ORAC-pyrogallol red (Oxygen Radicáis Absorbance Capacity). A fair correlation was found between total phenol content determined by Folin-Ciocalteau and DPPH consumption, both in crude methanol and n-hexane extracts. In particular, H. myrianthum and H. caprifoliatum showed the highest TRAP and ORAC-pyrogallol red values, respectively. This would imply that H. myrianthum contains a larger amount of antioxidants of lower reactivity. © 2009 Sociedad Chilena de Química.