| Abstract |
Many Hypericum species are widely used in Portugal, as well as in many other countries. In order to define the main components present in the water extracts, three Hypericum species, H. androsaemum and H. perforatum, obtained in the local supermarket, and H. undulatum, collected in an interior region of Portugal, were analysed for their inhibition of acetylcholinesterase and antioxidant activity. H. perforatum from five different suppliers was tested. All species were active, with IC(50) values between 0.62 +/- 0.06 and 1.79 +/- 0.37 mg dry extract/ml. HPLC-diode array analysis indicated that chlorogenic acid, rutin, hyperoside, isoquercitrin, and quercitrin were the main compounds present in the water extracts. Their inhibitory activities, determined as IC(50) values, were 196, 86, 66, 63 and 62 mu g/ml, respectively. The highest inhibitory activity was found with H. androsaemum and H. undulatum. All the species showed high antioxidant activity (DPPH test). Values of EC(50) between 9.0 +/- 0.2 and 18.4 +/- 0.8 mu g of dry extract/ml were obtained. (C) 2009 Elsevier Ltd. All rights reserved |
