Bio-guided fractionation of papaya leaf juice for delineating the components responsible for the selective anti-proliferative effects on prostate cancer cells

Alternative therapies against cancer cells with minimal or no effect on healthy tissues are highly sought after. Prostate cancer (PCA) is the second most frequently diagnosed malignancy in males. The Carica papaya L. leaf extract has been traditionally used by Australian aboriginal people for anticancer properties. In this study, medium polar fraction of papaya leaf extract that had shown anti-proliferative activity in PCA cell lines in vitro, in earlier studies, was further fractionated to 28 fractions by semi-preparative HPLC. Nine of these fractions were identified to possess selective anti-proliferative responses on PCA cells in comparison to non-cancerous cells of prostate gland origin. When these nine sub-fractions were mixed in various combinations, a combination containing six of the specific fractions (FC-3) showed the best potency. FC3 inhibited the growth of BPH-1, PC-3, and LNCaP cells in a concentration-dependent manner with an IC50 value