Croton lechleri sap inhibits in vitro proliferation of HT-29 human colon cancer cells

Croton lechleri L. (Euphorbiaceae) is one of the most widely used medicinal plants of the South American tropics. Its red viscous sap is reported to have a wide range of pharmacological and physiological actions [1]. It is used for wound healing, controlling diarrhoea, gastric ulcer healing and as a treatment for intestinal inflammation [2]. Thus, it appears that Croton l. has generalized benefits in gastrointestinal function. To evaluate its potential anti-tumour role we examined its effects on HT-29 human cancer cells. Cell proliferation was assessed by means of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Viability of cells treated with the sap from 0.1 ng/ml to 1 μg/ml decreased (p<0.001) in a dose dependent manner measured over a 24-h period. The concentration that induced a 50% inhibition of cell proliferation compared with controls was 1.6 ng/ml of sap. Croton l. seems undoubtedly to contain biologically active components that have anti-tumour and anti-bacterial agents [3] and vanilloid compounds [2]. These characteristics and the experimental data make this sap a potential source of new anti-cancer agents.