Specific anticancer activity of a new bisabolane sesquiterpene against human leukemia cells inducing differentiation in vitro.

A bisabolane sesquiterpene, rel-(1S,4R,5S,6R)-4,5-diacetoxy-6- [(R)-5-hydroxy-1,5-dimethylhex-3-enyl]- 3-methylcyclohex-2-enyl (Z)-2-methylbut-2 -enoate, which was newly isolated from the roots of Leontopodium longifolium, presented specific anticancer activity against human leukemia HL-60 cells, but did not inhibit proliferation of human hepatoma SMMC-7721 cells and human normal hepatocytes L02 cells. Nitroblue tetrazolium (NBT) reduction, phagocytosis of latex beads, and cell electrophoresis all demonstrated that this bisabolane sesquiterpene presented its anticancer activity against human leukemia HL-60 cells in vitro via inducing cell differentiation. Our results may have implications for treatment of human leukemia with the sesquiterpene.