Antioxidant Potential of Coconut Flour in Caco-2 Colon Cancer Cells

Abstract

Coconut Flour (CF) (Cocos nucifera L.) is a sweet by-product of coconut milk that has multifarious utility. The objective of this study was to investigate the chemopreventive potential of coconut flour extracts (defatted and whole) through determination of phytochemical content, antioxidative potential and cytotoxic effects on Caco-2 cells. Phytochemical (total phenolic, total flavonoid) content, Trolox Equivalent Antioxidant Capacity (TEAC), free radical-scavenging ability of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric Reducing Antioxidant Potential (FRAP) were determined according to standard protocols. Lactate dehydrogenase (LDH) release (cytotoxicity assay) was used to measure in vitro cell damage of Caco-2 colon cancer cells. Activity of antioxidant enzymes was determined with selected concentrations of extracts (25, 50 and 100 μg mLG). Apoptotic activity was assessed through the activity of caspase-3 and DNA fragmentation Enzyme-Linked Immunosorbant Assay (ELISA). Anti-inflammatory activity was assessed through measuring cycloxygenase-2 (Cox-2). Total phenolic and flavonoid content was 55.46±1.70 mg GAE/100 g and 17.84±2.33 mg CE/100 g. The TEAC was 0.65±0.05 μmol TE/100 g. The DPPH was IC50-74 mg mLG . The FRAP was 0.31±0.21 mmol/Fe gG and ORAC was 2387.78±88.68 μM TE gG 14.13±1.25 mmol/Fe gG. The LDH (%) release for 12 and 24 h was 45.8% at 50 μg mLG and 63.5% at 25 μg mLG. Caspase-3 was 15.46±0.639, Cox-2 was 0.30 U mLG and DNA fragmentation ELISA was 0.39 EF at 50 μg mLG. The results for the antioxidant and detoxification enzymes yielded: Glutathione-S-Transferase (GST) 2.12±0.32 nmol minG mLG, catalase (CAT) 24.65±0.40 U mgG, Glutathione Peroxidase (GPx) 30.4±0 nmol minG mLG, superoxide dismutase (SOD) 305.90±3.89 U mLG and glutathione (GSH) 24.4±0 nmol mLG. Results of this study revealed high phenolic and flavonoid content and suggested cytotoxic and antioxidative potential of coconut flour extracts.