Evaluation of limonoids against the murine P388 lymphocytic leukemia cell line.

A structure/activity study of selected limonoids from two plant families (Meliaceae and Rutaceae) of the Rutales order against the murine P-388 lymphocytic leukemia system was undertaken. The presence of both a 19 leads to 28 lactol and a 14,15 beta-epoxide group was found especially important for pronounced inhibition of the PS in vitro cell line. Substitution of an A-ring alpha,beta-unsaturated ketone (3-oxo-1-ene) for the lactol led to diminished activity, while reduction of the olefin caused complete loss of activity. At the dose levels employed, even very good PS in vitro inhibition was not translated into PS in vivo antineoplastic effects.