Anti-proliferative activity of Ensete superbum Roxb. Cheesman extract and its active principles on human colorectal cancer cell lines.

Ensete superbum Roxb. Cheesman (wild banana) is a plant traditionally used for the treatment of fever and diarrhea. On a preliminary screening, the ripe peel aqueous extract (PA) exhibited higher cytotoxicity (cell viability of 49% against HCT-15 at 75 µg/ml; and 46% against Caco2 at 50 µg/ml), superior anti-inflammatory (IC50 of 0.49 µg/ml), and greater anti-mutagenic activity at 500 µg/plate compared to the aqueous extracts of seed (SA), flower (FA) and bract (BA). Therefore, we further evaluated the anti-proliferative activity of PA and its fractions. The ability to inhibit the growth of cell lines (HCT-15 and Caco2) was used for the bio-guided fractionation and isolation of active compounds in PA using chromatographic techniques. Multiple extractions of the PA yielded the peel dioxane fraction (PD), and column fractionation of PD yielded eight compounds, of which three (Compound D-PDD, Compound E-PDE, and Compound G-PDG) possessed higher cytotoxic activity. At 10 µg/ml, the cell viability of HCT-15 was 50.1%, 46.5%, and 61.9%, respectively; Caco2 was 98.2%, 62.9%, and 64.7%, respectively, for PDD, PDE, and PDG. These compounds also showed apoptotic effect as evidenced by measuring the mitochondrial membrane potential, dual staining (acridine orange/ethidium bromide), DNA fragmentation, and the ROS status in colorectal cell lines. The UPLC-HRMS/MS, FTIR, and NMR data revealed the active compounds as quercetin-3-O-rutinoside, 3,5-dimethoxy-4-hydroxybenzoic acid, and 4',5,7-trihydroxyflavone. These findings indicate the anti-proliferative potential of PA, and warrant further investigation of its active principles in the amelioration of colorectal cancer in in vivo models. PRACTICAL APPLICATION: The potential of an underutilized crop as a source of therapeutic agents for colon cancer was established, as the study showed a high cytotoxic activity of wild bananas against HCT-15 and Caco2 cell lines. Bioactivity guided fractionation of peel fraction identified the active compounds present in wild banana, and their anticancer activity was attributed to the induction of cell death. The study indicated that wild banana has the potential to inhibit the growth of colon cancer cells.