Bioassay-guided fractionation of Euphrasia pectinata Ten. and isolation of iridoids with antiproliferative activity

The use of aerial parts of Euphrasia pectinata Ten. usually known as Eyebright, is one of the commonestfolk remedy in many European and Asian countries to treat eye problems. By a bioassay-guidedfractionation of the dichloromethane fraction of E. pectinata methanolic extract, following theantiproliferative activity on different cancer cell lines (MCF-7, HeLa, LNCaP, ACHN and C32), the newiridoid euphrasin (1), and the known campsinol (2), artselaenin A (3), and artselaenin B (4) were isolated.The structure of euphrasin (1) was determined by spectroscopic methods. All compounds screened bySRB assay exhibited antiproliferative activity in a concentration dependent-manner. In particular,euphrasin (1) showed a promising activity against LNCaP and HeLa cells with IC50 values of 0.1 and0.2 microM, respectively. Signficative results were also obtained with campsinol (2) with IC50 value of 1.9 microMon endometrial cancer cells.