Astilbic acid induced COLO 205 cell apoptosis by regulating Bcl-2 and Bax expression and activating caspase-3

AIM: To investigate the effect of astilbic acid (3β6β-dihydroxyolean-12-en-27-oic acidAA) on human colorectal carcinoma COLO 205 cell proliferation and apoptosis. METHODS: Proliferation of COLO 205 cells was measued by MTT assay. Content of DNA in COLO 205 cell was measued by modified diphenylamine assay. AA-induced morphological changes was observed with fluorescence microscope and transmission electron microscope . DNA fragmentation was visualized by agarose gel electrophoresis. Apoptosis rate and cell cycle distribution were determined by flow cytometric analysis. Expressions of Bcl-2 and Bax proteins were visioned by immunohistochemical analysis. The change of relative mitochondral transmembrane potential (MTP) in COLO 205 cell was analyzed with FCM after rhodamine 123 staining. RESULTS: The IC50 (96 h) of AA for inhibiting COLO 205 cell proliferation was 61.56±0.34 umol/L. AA induced a marked concentration- and time-dependent inhibition of COLO 205 cell proliferation and reduced the DNA content i