Antitumor effect of extracts from moutan cortex on DLD-1 human colon cancer cells in vitro.

Moutan cortex, the root bark of Paeonia suffruticosa Andrews (Paeoniaceae), is a traditional Chinese medicine widely used for the treatment of various diseases. In the present study, we examined the antiproliferative effect and apoptosis-inducing activity of paeonol and the crude total glycosides (CTG) extracted from moutan cortex against DLD-1 human colon cancer cells in vitro. Cell viability was measured using the WST-8 assay. Apoptosis was detected by Hoechst 33258 fluorescence staining and flow cytometry. Paeonol and the CTG significantly reduced cell viability in a dose- and time-dependent manner. The induction of apoptosis in DLD-1 cells was characterized by morphological changes and an increased percentage of hypodiploid cells. After treatment for 48 h with paeonol (400 µg/ml) or CTG (200 µg/ml), the ratio of apoptotic cells reached 34.79 and 48.12%, respectively. The findings obtained indicate that paeonol and the CTG extracted from moutan cortex have a significant growth-inhibitory effect on human colon cancer cells. This effect may be related to the induction of apoptosis.