Evaluation of in vitro antioxidant and anti-proliferative effect of defatted extract of cocos nucifera kernel on human breast cancer cell line�

Abstract

Objective: Biologically active antioxidant dietary components have attracted public interest as effective alternative for the successful treatment and prevention of several types of cancer. The present study was designed to evaluate the in vitro antioxidant effects and potential benefit of using coconut kernel extract in preventing the proliferation of human breast cancer cell lines MCF-7. STUDY DESIGN: Defatted extract from coconut kernel (CKf) was obtained using methanol by soxhlet method. Radical scavenging and prevention of human LDL oxidation by CKf was done in vitro. The cytotoxic effect on MCF-7 cells were evaluated using MTT assay after treatment with different concentrations of CKf (12.5- 100 mg/mL) for 24 hrs. Cell apoptosis and nuclear changes were determined us¬ing acridine orange/Ethidium bromide and DAPI staining. Intracellular production of reactive oxygen species (ROS) were studied using the fluorescent DCFH-DA staining. MitoSox Red fluorescent stain was used to evaluate the effect of CKf on the generation of superoxide radicals within the mitochondria of MCF-7 cells. Results: It was showed that CKf significantly scavenged the free radicals and prevented the chemically induced LDL oxidation. MCF-7 cell viability was found to be decreased in a dose dependent manner following treatment with the CKf . Cytoxicity appeared to be absolute in all concentrations of CKf (>35mg/ml). AO-EB and DAPI staining confirmed that the treatment with CKf induced apoptosis and nuclear damage as distinctly visible in cells, as a result the nuclear/cellular damage and poor mitochondrial membrane potential (MMP) appears to be an indirect consequence of the excessive generation of reactive oxygen species (ROS) and superoxide radicals shown through DCFH-DA and MitoSox staining. Conclusions: These results proved that CKf have both significant antioxidant and anti-proliferative potential against MCF-7 cell line growth by inducing cell death through free radical production and nuclear damage.