certain decorative indoor - plant cultivars are derived from toxic wild plant species . 
 native members of the euphorbiaceae ( spurge ) contain highly irritating and tumor - promoting diterpene esters . 
 plant breeders and gardeners are constantly searching for less toxic cultivars of the popular euphorbiaceae indoor plants . in this investigation , 22 commercial cultivars of euphorbiaceae indoor plants were examined for tumor promoter contents by high - performance liquid chromatography ( hplc ) . 
 cultivars of e. milii ( e. lomii hybrids ) , and in particular e. leuconeura , contained ingenol derivatives , whereas cultivars of e. pulcherrima and codiaeum variegatum were devoid of these compounds . 
 tumor - promoting activity was assessed by induction of a luciferase reporter gene , which was placed under the control of an epstein - barr virus early antigen promoter . 
 the response was closely correlated with ingenol ester content ; the latex of the two e. leuconeura cultivars tested gave the strongest response . 
 the hplc and bioassay methods used in this study provide a basis for the development of nontoxic indoor - plant cultivars and perhaps for consumer - oriented labeling.imagesfigure 1figure 2figure 3figure 4