In vitro anticancer activity of Eclipta alba whole plant extract on colon cancer cell HCT-116

Abstract

Backgrounds: Colon cancer is the third most deadly and one of the most diagnosed diseases in the world. Although routine screening and early detection during last decades has improved the survival, colon cancer still claims hundreds of thousands lives each year worldwide. Surgery and chemotherapy is mainstay of current treatment, nevertheless toxicity associated with this treatment underscores the urgency of demand of a better therapeutics. Close to 50% of current chemotherapeutic drugs are direct or indirect descendants compounds isolated from medicinal plants, which indicate plants are great potential sources of novel therapeutics. In our literature review we found Eclipta alba to posses many pharmacological activities, including those with anticancer potentials. However, no study on anticancer activity of this kind has been reported.

Methods: Phytochemicals were extracted by maceration method from shade dried whole plant of Eclipta alba using methanol as a solvent. The anticancer effect of extract was investigated on various cancer cell lines like human colorectal carcinoma (HCT-116), human prostate cancer (PC-3), Michigan cancer foundation-breast cancer (MCF-7) and renal cell carcinoma (RCC-45). We have also studied the effects on normal human embryonic lung fibroblast cell (WI-38) using MTT (methyl thiazoldiphenyltetrazolium bromide) assay, clonogenic (colony formation) and migration assay. Finally obtained results were analyzed using ANNOVA and Dunnett's test.

Results: Results obtained from MTT assay revealed that the methanolic extract of Eclipta alba carried significant (p < 0.005) specificity against HCT-116 cells as compared to the other cancer cells. This extract also showed minimal or nontoxicity to WI-38 cells. Migration as well as clonogenic assays also confirmed the anticancer potential of the extract against HCT-116 cells.

Conclusion: This is a unique finding of its kind because the specific anticancer effect with minimal toxicity on normal cells has not been reported on Eclipta alba extract. Finally this finding opens up a great possibility to develop a novel antitumor drug candidate against deadly colon cancer in the future.

Keywords: Anticancer; Colon cancer; Eclipta alba; Nontoxic; Normal cells; Specificity.

Fig. 1

The MTT assay results show Eclipta alba methanol extract (EAME) exhibits specific growth inhibition in colon cancer cells (graph a) as compared to other selected cancer cells (graph panel b, c and d), the results also reveals extract shows negligible toxicity to the normal cell (graph e). Right bottom graph shows relative sensitivities of the cells that were compared by plotting their IC-50 values

Fig. 2

The Phase contrast image shows specific and significant morphological change in HCT-116 cells as compared to other cancer cells (RCC-45, PC-3 and MCF-7) and also normal cell (WI-38) as treated with Eclipta alba methanol extract at their IC-50 concentrations

Fig. 3

a Eclipta alba methanol extract (EAME) Inhibit colony formation of HCT-116 cells at the indicted concentrations compared to the control group. b Bar graph representing the density of colonies shown in panel a

Fig. 4

Eclipta alba methanol extract inhibits migration of HCT-116 cells: Phase contrast images of cells after treatment with the vehicle (DMSO) or indicated doses of the extract as described in Methods