Cytotoxic falcarinol oxylipins from Dendropanax arboreus.

The crude organic extract of Dendropanax arboreus was selected as a candidate for bioassayguided fractionation on the basis of its relatively selective cytotoxicity to a subset of cell lines within the National Cancer Institute's disease-oriented in vitro tumor-screening panel. The major compound responsible for the in vitro cytotoxicity was falcarinol (1). Several other known compounds were isolated and found to be cytotoxic, including dehydrofalcarinol (2), a diyenne (3), falcarindiol (4), and dehydrofalcarindiol (5). In addition, two novel polyacetylenes, dendroarboreols A (6) and B (7), were isolated and characterized by standard and inverse-detected NMR methods. Compounds were selected from this series for absolute stereochemical determination using the modified Mosher method and preliminary in vivo evaluation using a LOX melanoma mouse xenograft model.