Antioxidant and antineurodegenerative properties of St. John's-wort dry extract

Different biological activities of Hypericum perforatum L. dry extract was tested in this study. Antioxidant activity was evaluated by four different assays. Antineurodegenerative activity was tested using acetylcholinesterase (AChE) and tyrosinase inhibitory activity assays. In all four antioxidant assays, concentration dependent manner was noticed in the activity of tested extract. The most active was the highest applied concentration (500 μg/ml). In DPPH test, extract applied in dose of 200 μg/ml showed similar or higher radical scavenging activity compared to the dose of 100 μg/ml applied for standard substances BHA and BHT. The lowest antioxidant activity for the extract was detected in ABTS test. All applied concentrations of dry extract were significantly more potent than vitamin C in ß-carotene test. Moreover, the extract reached 40.31 and 45.56 % of the inhibition in AChE and TYR assays, respectively. In both cases, the most active concentration of the extract was 200 µg/ml