Synergistic protective effects of curcumin nano-emulsion and virgin coconut oil against thermal oxidation of sunflower oil and its hepatorenal toxicity in rats

Introduction: Repeated heating of vegetable oils leads to the generation of toxic oxidation products, which activate systemic oxidative stress and cause multi-organ injuries. This study examined the hepatorenal synergistic protection of Curcumin Nano-Emulsion (CNE) and virgin coconut oil (VCO) against the toxicity of thermally stressed sunflower oil (HSO) and explored the underlying antioxidant and anti-inflammatory mechanisms. Methods: by measuring peroxide value, p-anisidine value, total polar compounds, and toxic aldehydes. For the in vivo study, sixty-four male Wistar rats were fed different oil-based diets for two months. Biochemical parameters, oxidative stress markers, inflammatory indices, and histopathological changes in liver and kidney tissues were assessed. Immunohistochemical analysis was performed to evaluate NF-κB and Nrf2 signaling pathways. Results: Supplementation of HSO with VCO and CNE significantly improved oxidative stability compared with individual treatments and TBHQ, with marked reductions in peroxide value, p-anisidine value, total polar compounds, and toxic aldehydes. HSO induced significant hepatorenal injury, dyslipidemia, oxidative stress, and inflammation in rats. The combined treatment (HSO + VCO + CNE) markedly ameliorated these alterations, nearly restoring biochemical parameters to normal levels and minimizing histopathological damage. A strong downregulation of the NF-κB pathway and activation of the Nrf2 antioxidant pathway were observed. Discussion: Co-administration of curcumin nano-emulsion and virgin coconut oil effectively enhances the oxidative stability and safety of thermally stressed edible oils. These findings suggest a promising natural strategy to reduce oil-induced toxicity and support safer industrial oil processing approaches aligned with public health protection.