Evaluation of anti-cancer potential of saffron extracts against kidney and bladder cancer cells

Crocus Sativus L. (saffron) has been used for centuries as a medicinal plant in traditional medicine. Its main bioactive secondary metabolites, which include crocins, crocetin, picrocrocin and safranal, are known to possess significant antioxidant as well as anti-proliferative activities. With the aim to test the activity of saffron on kidney and bladder cancer cell lines, we tested the effect of extracts obtained from dried stigmas derived from different Italian regions (Lombardy and Tuscany) in two different years, on the cell viability. The treatment with saffron extracts showed a significant reduction of cell viability in most of our tumoral cellular systems, while the standards crocin and safranal alone at the same concentrations did not exerted any cytotoxicity. When the extracts and standards were mixed together, they exerted a milder inhibition of cell viability, indicating that the antitumor activity is likely a result of the synergy of the various compounds. In addition, in a circular economy vision, we recovered Crocus Sativus flowers and tested them on cancer cells, demonstrating a consistent reduction of cell viability, while kaempferol (main compound present in flower extracts) did not show compatible results. Our results extend the interests around saffron-derived bioactive molecules for their potential in therapeutics.