Orobanche crenata extracts exerts antitumor activity “in vitro”

Colorectal cancer (CRC) is the second deadliest cancer, causing 900 000 deaths worldwide. Despite progress in diagnosis and treatment, chemotherapy significantly compromises the quality of life of oncologic patients. Therefore, the use of adjuvants endowed with anticancer property could be considered a good strategy to reduce the dose of chemotherapy improving the health conditions of oncologic patients. Thus, in the present work, we investigated the anticancer activity of Orobanche crenata leaf extract against two different colorectal cancer cell lines Caco-2 and HCT-116. The activity of the aqueous extract was compared to the standard drug Cisplatin. Human colon cancer cells (Caco-2 and HCT-116) were treated with O. crenata aqueous extracts (10 - 160 μg/ml) or with cisplatin (0.03 – 30 μg/ml) for 24, 48 and 72h. Human dermal fibroblasts were used as control cell line. After treatments, we evaluate cytotoxicity by MTT assays and apoptosis (by Annexin V/Propidium Iodide assays) and both BAX and Bcl-2 protein levels (by western blot analysis). Extract exhibits cytotoxicity in Caco-2 in a dose and time-dependent manner significantly reducing cell viability. Co-treatment with 40 μg/ml of extract for 48h potentiated the sub-toxic effect of cisplatin. Hoechst and Annexin V/PI staining showed the induction of apoptosis by extract in Caco-2 cells; this data were confirmed by increased levels of Bax/Bcl-2 ratio. These findings suggest that O. crenata aqueous extracts exert an anti-cancer effect enhancing apoptosis in Caco-2 cells thus considering a promising therapeutic adjuvant against various cancer cell types.