Anti-proliferative effect of Moringa oleifera Lam (Moringaceae) leaf extract on human colon cancer HCT116 cell line

Purpose: To investigate the in vitro anti-proliferative effect and mechanism of action of Moringa oleifera Lam. leaf extract on human colon carcinoma HCT116 cell line. Methods: M. oleifera leaves were extracted with methanol. It was fractionated by Sephadex LH-20 column chromatography. Several fractions were identified by thin layer chromatography (TLC), proton nuclear magnetic resonance (H-1 NMR) and mass spectrometry (MS). The growth inhibitory activity and mechanism of action of the extracts in HCT116 colon cancer cells were investigated by 3-(4, 5-dimethylthiazolyl- 2)-2,5-diphenyltetrazolium bromide (MTT) assay and Western blotting. Results: Successive fractions from M. oleifera leaf crude extracts by column chromatography were combined into four pooled batches (MOL1 -MOL4) according to their absorbance at 260 nm and TLC pattern. MOL2 and MOL3 contain astragalin and isoquercetin, respectively. The results from MTT assay indicated that cell proliferation was significantly (p < 0.05) inhibited in a concentration-dependent fashion, especially by MOL2, MOL3 and MOL4. MOL2 and MOL3 exhibited a stronger cell growth inhibition than their major ingredients. The anti-proliferative activity of MOL2 -MOL4 in HCT116 colon cancer cells was mediated by downregulation of ERK1/2 phosphorylation. Conclusion: M. oleifera leaf extract has a strong anti-proliferative activity which is exerted by decreasing ERK1/2 phosphorylation. Thus, the extract has a potential for use in cancer chemoprevention.