Antioxidant properties, total phenolic, total carotenoid and chlorophyll content of anatomical parts of Hypericum foliosum

Methanolic extracts from eight anatomical parts of the endemic Azorean Hypericum foliosum were evaluated for their potential antioxidant activity and basic classes of bioactive compounds. The results revealed that one single method is not enough to perform an accurate estimation of the antioxidant potential. The reducing power, prevention of beta-carotene/linoleic acid system oxidation and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities are very promising in comparison with reference compounds, while none of the extracts showed significant iron-chelating ability. On the other hand, a pro-oxidant action was observed for six of the extracts regarding the inhibition of protein oxidative damage. Among all assayed samples, the stems showed significant antioxidant properties, a fact which may be related to the high total phenolic content (386.89 mg of gallic acid equivalents/g dry extract), which is twice than the majority of the other samples. The present data on H. foliosum revealed a potential source of powerful antioxidants, for further detailed phytochemical investigation.