目的 观察茯苓酸对人乳腺癌MDA-MB-231细胞增殖及凋亡的影响，并初步探讨作用机制。方法 乳腺癌MDA-MB-231细胞与不同浓度（1、2、5μmol/L）的茯苓酸共孵育，采用CCK-8细胞增殖与活性检测试剂盒检测细胞存活率；流式细胞术Annexin V/PI双染色检测细胞凋亡；Western blotting法检测多聚腺苷二磷酸核糖聚合酶（PARP）及与细胞凋亡相关蛋白的表达。结果 茯苓酸能够剂量和时间依赖性地抑制MDA-MB-231细胞的增殖，并可诱导MDA-MB-231细胞凋亡。浓度为1、2、5μmol/L的茯苓酸作用MDA-MB-231细胞48h后，细胞凋亡率显著增加至25.6%、59.4%、87.2%，明显高于对照组凋亡率（5.4%）；经过1、2、5μmol/L茯苓酸分别处理48h后，实验组MDA-MB-231细胞中凋亡蛋白标志物PARP裂解量升高，且呈剂量依赖性。结论 茯苓酸能抑制MDA-MB-231细胞的增殖并诱导其凋亡，其作用机制与激活PARP有关。

Objective To study the potential apoptotic effect of pachymic acid isolated from Poria cocos, a traditional Chinese medicinal fungi, on human breast cancer cells.Methods Pachymic acid was isolated and purified from the crude ethanol extract of P.cocos. Human breast cancer cell line MDA-MB-231 cells were treated with pachymic acid. Relative cell viabilities were determined by the Cell Counting Kit-8 assay; Apoptosis was analyzed by Annexin V/PI dual staining with flow cytometry; The protein expression levels of poly ADP ribose polymerase (PARP) and other apoptotic related proteins were detected by Western blotting.Results Pachymic acid reduced the viability of MDA-MB-231 cells dose-and time-dependently. Moreover, pachymic acid induced the apoptosis in MDA-MB-231 cells. The data of Western blotting showed that pachymic acid u p-regulated the expression level of PARP, in a dose-dependent manner. In addition, apoptosis-related proteins like Bax, Bcl-2, and casapases were all affected by pachymic acid.Conclusion Pachymic acid could induce the apoptosis in human breast cancer cells, which provides a novel information for clinical application of pachymic acid and its preparations for the breast cancer patients.