Crocus sativus stigma extract and its major constituent crocin possess significant antiproliferative properties against human prostate cancer

"Saffron, the dry stigmas of Crocus sativus, is mainly used as a spice and is known to have anti-cancer properties. In this study we investigated the cytotoxicity of Saffron extract (SE) and its major constituent crocin in different malignant and non-malignant prostate cancer cell lines. All cells were incubated with different concentrations of SE (0.2–8 mg/ml) or crocin (0.1-4 mM). Cell viability was quantized by MTT assay. Apoptotic cells were determined using DNA fragmentation assay by flow cytometry. Both saffron extract and crocin were not toxic at any of concentrations used whereas cell proliferation was reduced in a concentration- and time dependent manner with IC50 values ranged between 400 and 4000 µg/ml for SE and between 0.26 and 0.95 mM/ml for crocin. Non-malignant prostate epithelial cells were not affected. Apoptosis was very low in presence of SE whereas significant apoptosis was observed in cells treated with crocin. Crocin-induced apoptosis could be inhibited by pan-caspase inhibitors, indicating a caspase-dependent activation. Bax protein expression was also increased whereas no significant modulation in bcl2 protein was evident. Taken together our results suggest that the saffron extract has antitumor effects in prostate cancer cells and can be considered a good bioactive feeding support."