Antiproliferative Xanthones of <i>Terminalia </i><i>calcicola</i> from the Madagascar Rain Forest

A bioassay-guided fractionation of the EtOH extract of the Madagascan plant Terminalia calcicola led to the isolation of two new cytotoxic xanthones, termicalcicolanone A (1) and termicalcicolanone B (2). The structures of the new compounds were established on the basis of one- and two-dimensional NMR spectroscopic data. Both compounds showed modest antiproliferative activity toward the A2780 human ovarian cancer cell line.