Composition and antioxidant activity of different St. John Wort (Hypericum perforatum L.) extracts

Current literature reports a wide variability in active compounds content in marketed Hypericum (Hypericum perforatum L.) preparations. In order to avoid influences by soil, climate, collection time and storage, several extracts were prepared, with different solvents, from a single stock of plant drug, collected from the wild. They were high performance liquid chromatography (HPLC) analyzed, and results were coupled with an evaluation of the antioxidant activity in vitro of each extract. Also water extracts maintained a good activity, although they were obviously lacking hypericin and hyperforin. In this sense, the home made St. John’s wort teas should be re-valued as possible beverages with interesting antioxidant properties.