ABSTRACT
<p><b>OBJECTIVE</b>To investigate the cytotoxic effect of extracts of Trichosanthes kirilowi (TK) root on Hela cells in vitro and its probable anti-tumor mechanism.</p><p><b>METHODS</b>The cytotoxic effect in vitro on the growth of Hela cells was evaluated by microculture tetrazolium assay (MTT). Cell ultrastructural changes were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and DNA agarose electrophoresis was performed to determine apoptosis and biochemical changes of Hela cells.</p><p><b>RESULTS</b>Exposure of Hela cells to TK extracts for 24-48 hrs resulted in a cell growth arrest, which showed in a time- and dose-dependent manner (r > 0.880, P < 0.01). With SEM and TEM, marked changes were observed, including microvilli disappearance or reduction, cell membrane vesiculation, cell shrinkage, condensation of chromosomes and apoptotic bodies with complete membrane. Besides, the apoptosis of Hela cells was confirmed by typical DNA ladder formation on gel electrophoresis.</p><p><b>CONCLUSION</b>Extracts of TK has a marked anti-tumor activity and could induce apoptosis of Hela cells.</p>