Virgin coconut oil complements with its polyphenol components mitigate sodium fluoride toxicity in vitro and in vivo

Abstract

Virgin coconut oil (VCO), prepared from fresh coconut kernel without any chemical refining, is an emerging functional food. The pharmacological benefits of VCO are believed to be due to the natural combination of phenolics. Although cell culture studies have demonstrated the antioxidant activity of VCO under different oxidative stress conditions, a valid in vivo demonstration of the antioxidant activity of VCO is yet to come. Sodium fluoride (NaF), an environmental pollutant, is widely used to induce oxidative stress in cell culture models and rodents to test the antioxidant potential of several compounds. Herein, VCO and its polyphenolic (VCOP) and non-phenolic oil fraction (VCOF) were individually tested in fluoride-exposed normal intestinal cells (IEC-6) and mice to address their contribution to the documented antioxidant potential. It was found that pretreatment of VCOP (40 µg/mL) was effective in mitigating the fluoride-induced cell death when compared to VCO (200 µg/mL) and VCOF (160 µg/mL). Further, exposure to fluoride (10 mM), increased the intracellular ROS measured based on the dichlorofluorescein (DCF) fluorescence, and this, in turn, was significantly reduced when the cells were supplemented with VCOP. Oral administration of VCO (2 mL/kg bwt) reversed the drop in the hepatic catalase and SOD activities to near normal with a minimal level of lipid peroxidation in fluoride intoxicated mice. However, VCOP and VCOF were less effective in lowering the fluoride-induced increase in hepatic oxidative stress markers. It is reasoned that the oil components of VCO complement the natural antioxidant molecules resulting in an overall increase in their bioavailability.