There is provided use of a cyclic compound or a pharmaceutically active salt thereof in the manufacture of a medicament to prevent and/or inhibit and/or arrest cell cycling, wherein the cyclic compound comprises at least one ring,wherein Group I and Group II, independently of each other, are attached to a ring of the cyclic compoundwherein Group I is a hydrocarbyl or an oxyhydrocarbyl group andwherein Group II is a group of the formulaX is P or S when X is P, Y is ═O or S, Z is —OH and R is hydrocarbyl or H when X is S, Y is ═O, Z is ═O, and R is hydrocarbyl or N(R1)(R2), wherein each of R1 and R2 is independently selected from H or a hydrocarbyl group.
