| abstract |
Together with the know crambescidins (1-5) and ptilomycalin A (6), two new minor crambescidins 834 (7), 818 (8) with a chlorinated spermidine unit and four new minor crambescidins 673 (9), 687 (10), 657 (11) and 13, 14, 15-isocrambescidin 657 (12) without a spermidine derivative unit have been obtained by FABMS guided isolation from extracts of the Mediterranean sponge Crambe crambe. Their structures were elucidated by interpretation of spectral data (see Figures 4-9). In a parallel bioassay against L1210 murine leukemia cells, crambescidins 834 (7), 818 (8) and 657 (11) were shown to be five times as cytotoxic as the knows crambescidin 816 (1). Crambescidins with a spermidine or spermidine derivative unit also exhibited antimicrobial activity against Rhodotorula glutinis. |