Melampomagnolide B: A new antileukemic sesquiterpene

Melampomagnolide B (3) has been identified as a new antileukemic sesquiterpene. A biotin-conjugated derivative (4) of melampomagnolide B was designed and synthesized in order to elucidate its mechanism of action. A study of the biochemical interactions of the biotin probe suggests that melampomagnolide B derives its remarkable selectivity for leukemic cells over normal hematopoietic cells from its unique ability to exploit biochemical differences between the two cell types.