Gymnasterkoreaynes A-F, cytotoxic polyacetylenes from Gymnaster koraiensis

Six new polyacetylenes, gymnasterkoreaynes A-F (1-6), were isolated from the roots of Gymnaster koraiensis, together with 2,9,16-heptadecatrien-4,6-diyn-8-ol (7) and 1,9,16-heptadecatriene-4,6-diyn-3,8-diol (8), by bioassay-guided fractionation using the L1210 tumor cell line as a model for cytotoxicity. The structures of compounds 1-6 were established spectroscopically, which included 2D NMR experiments. Gymnasterkoreaynes A-F (1-6) are linear diacetylenes and are structurally related to falcarinol, panaxynol, panaxydiol, and panakytriol. Of the compounds isolated, gymnasterkoreaynes B (2), C (3), F (6), and 1,9,16-heptadecatrien-4,6-diyn-3,8-diol (8) exhibited significant cytotoxicity against L1210 tumor cells with ED50 values of 0.12-3.3 mug/mL.