BISTRAMIDE-A, BISTRAMIDE-B, BISTRAMIDE-C, BISTRAMIE-D, AND BISTRAMIDE-K - A NEW CLASS OF BIOACTIVE CYCLIC POLYETHERS FROM LISSOCLINUM-BISTRATUM

The isolation and characterization is described of four novel cyclic p olyethers, bistramides B [2], C [3], D [4], and K [5], which are close ly related to the previously reported bistramide A [1] from the New Ca ledonian urochordata Lissoclinum bistratum. The structures of these me tabolites were defined by spectroscopic methods. The four compounds ex hibited in vitro cytotoxicity toward six tumor cell lines, including t he human non-small cell lung carcinoma (NSCLC-N6) line. Cytofluorimetr ic analysis with bistramide K showed a complete block of NSCLC-N6 cell s in the G(1) phase. Bistramide D and particularly bistramide K are le ss toxic than bistramides A, B, and C and are thereby effective in viv o against NSCLC-NG.