RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Rheum officinale Baill. (Da Huang) is one of the herbs commonly used in traditional Chinese medicine formulae against cancer. The traditional decoction is similar to the water extract used in the present study. AIM OF THE STUDY: The water extract of Da Huang was investigated to see if it possesses anticancer effects through apoptotic pathways. MATERIALS AND METHODS: Human lung adenocarcinoma A549 and human breast cancer MCF-7 cell lines were treated with different concentrations of Da Huang water extract at different time intervals. Growth inhibition was detected by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] and colony formation assays; apoptosis was detected by cell morphologic analysis, DNA fragmentation analysis and COMET assay. RESULTS: Da Huang water extract was found to have significant growth inhibitory effects on both A549 and MCF-7 cell lines with IC(50) values 620+/-12.7 and 515+/-10.1 microg/ml, respectively. Growth inhibitory effects were dose- and time-dependent. A significant decrease in cell number, DNA fragmentation and single DNA strand breakages were observed in the Da Huang water extract treated A549 and MCF-7 cells. CONCLUSIONS: This suggests that the water extract of Da Huang exerts potential anticancer activity through growth inhibition and apoptosis on MCF-7 and A549 cells lines.