| abstract |
The present invention provides a substantially purified compound having the structure: ##STR1## wherein R 1 to R 9 are defined; or a salt of the compound, and provides pharmaceutical compositions comprising a compound of the invention and a pharmaceutically acceptable carrier. The invention also provides methods of reducing or inhibiting mitosis of a cell by contacting the cell with a compound of the invention, which blocks the cell at the G2/M phase of the cell cycle. The invention also provides a method of reducing the severity of a pathology characterized, at least in part, by undesirable proliferation of a population of cells in a subject by administering to the subject a compound of the invention in an amount sufficient to reduce or inhibit proliferation of the population of cells. |