The schweinfurthins are prenylated stilbenes isolated from Macaranga schweinfurthii that are significantly toxic to a number of cancer cell lines.  Schweinfurthins have a common tricyclic component exemplified in the structure of 3-deoxy- schweinfurthin B (1).  As part of our ongoing efforts to elucidate structure activity relationships in the 3-deoxyschweinfurthin series we synthesized various analogs of this compound including the R,R,R- and S,S,S-enantiomers.  These compounds were tested for cytotoxicity through the NCI 60-cell line screen, which identified RPMI-8226 myeloma cells as particularly sensitive.  To further elucidate their mechanism of toxicity, the effects of schweinfurthins on growth of RPMI-8226 cells were studied by [³H]-thymidine incorporation, western blot, and flow cytometric analysis. We will present data detailing schweinfurthin-induced cell cycle arrest in these cells, emphasizing similarities and differences in activity dependant on stereochemistry in the tricyclic region. 

(1) R,R,R-3-deoxy-schweinfurthin B