Structural requirements for biological activity among antileukemic glaucarubolone ester quassinoids.

A C-15 ester substituent is required for significant antileukemic activity among the glaucarubolone ester quassinoids, and variations in the ester group are not accompanied by particularly marked changes in antileukemic activity. Unsaturation at the 3,4 position is advantageous for optimal activity, and hydrogenation of this double bond results in marked diminution in both cytotoxicity toward KB cells in tissue culture and inhibitory activity against the P-388 lymphocytic leukemia in mice.