Assessment of cytotoxicity and genotoxicity of stem bark extracts from Canarium odontophyllum Miq. (dabai) against HCT 116 human colorectal cancer cell line

Background: Canarium odontophyllum Miq. is a plant species widely known as 'dabai' and can be vastly found in Sarawak. The aim of this study was to assess the cytotoxic and genotoxic effect of extracts from stem bark of C. odontophyllum against HCT 116 human colorectal cancer cell line. Method: The IC50 values of the aqueous, methanol, and acetone extracts against HCT 116 cells as well as the acetone extract against human colon fibroblast cell line CCD-18co were determined using the MTT assay. The concentration of the extracts ranged from 12.5 to 200 mu g/ml at treatment time of 24, 48 and 72 h. Annexin V-FITC/PI labelling assay was employed to determine mode of HCT 116 cell death induced by acetone extract at 48 h. The DNA damage induced by the extract in HCT 116 cells was detected using alkaline comet assay at 30 min of IC10 and IC25 treatment. Results: Acetone extract exhibited the highest cytotoxic effect against HCT 116 cells compared to methanol and aqueous extract at 24, 48 and 72 h. Despite no cytotoxic effect by acetone extract against CCD-18co cells at 24 and 48 h, however at 72 h, CCD-18co cells proliferated. Apoptosis assessment using Annexin V-FITC/PI labelling assay revealed that the primary cell death was via apoptosis after 48 h treatment. Low doses of acetone extract from stem bark of C. odontophyllum showed significant DNA damage in HCT 116 cells with tail moment of 6.187 +/- 0.718 A. U and 7.877 +/- 0.142 A. U, respectively. Conclusions: Acetone extract from stem bark of C. odontophyllum has high potential in the development of anticancer agent against HCT 116 cells with no cytotoxic effect against human colon fibroblast cells.