Background & objectives: Epithelial ovarian carcinoma seems to be one of the most lethal cancer types among all gynecological malignancies. The conventional course of therapy includes chemotherapy. Actually most cancers respond to chemotherapy but in the long run drug resistance and side effects cause treatment failure. In addition, milk thistle (silibinin), a plant that has been used from ancient time because of its good effects on different organs, determined to have powerful antioxidant activity.  The aim of this study was to examine the effect of silibinin on SKOV-3 cancer cell line after 48 hours of treatment and P21 gene expression which involves in cell cycle progression.

Methods: The human epithelial ovarian cancer cell line SKOV-3 was cultured as monolayer in 25 cm² flask in RPMI-1640 medium supplemented with 10% fetal bovine serum (FBS). Then the numbers of live cells were calculated using hemocytometer method and the cells were seeded in 96-well flat-bottomed culture plates and treated with different concentration of Silibinin. MTT assay was carried out to determine cell viability. To study P21 gene expression, RNA extraction and cDNA synthesis were carried out and real-time PCR was done.

Results: Cell growth was inhibited considerably by Silibinin treated groups compared with control after 48 hours. P21 gene expression was increased as well.

Conclusions: According to the results, Silibinin can be used as an effective drug in cancer treatment. More studies on animal models are also suggested.