J Appl Biomed 16:281-288, 2018 | DOI: 10.1016/j.jab.2018.02.003

Antioxidant and anti-inflammatory mechanisms of polyphenols isolated from virgin coconut oil attenuate cadmium-induced oxidative stress-mediated nephrotoxicity and inflammation in rats

Ademola C. Famurewa^a,*, Abumchukwu J. Ejezie^b, Chioma S. Ugwu-Ejezie^c, Ebele J. Ikekpeazu^d, Fidelis E. Ejezie^d

^a Federal University, Ndufu-Alike, Faculty of Basic Medical Sciences, Department of Medical Biochemistry, Ikwo, Ebonyi State, Nigeria

^b University of Nigeria, Enugu Campus, College of Medicine, Department of Anatomy, Enugu State, Nigeria

^c University of Nigeria Teaching Hospital, Department of Haematology/Immunology, Ituku-Ozalla, Enugu State, Nigeria

^d University of Nigeria, Enugu Campus, College of Medicine, Department of Medical Biochemistry, Enugu State, Nigeria

Purpose
Cadmium (Cd) is a classic cumulative nephrotoxicant and literature suggests that its toxicity is associated with oxidative stress and inflammation which contribute to pathologies in various tissues. We sought to investigate whether polyphenols isolated from virgin coconut oil (VCO) would modulate nephrotoxicity and inflammation induced by Cd in rats.
Methods
Rats were administered polyphenols prior to and along with Cd (5 mg/kg, orally) for 7 weeks. Serum markers of renal damage, interleukin-6 (IL-6), C-reactive protein (CRP) and nitric oxide (NO) were evaluated; renal activities of antioxidant enzymes, as well as malondialdehyde (MDA) and reduced glutathione (GSH) content were determined. Histopathologic alterations were evaluated to define kidney damage.
Results
Cadmium exposure induced nephrotoxicity and oxidative stress evident by significantly increased serum levels of creatinine, urea, and uric acid along with remarkable depression in renal activities of antioxidant enzymes and GSH with prominent increase in MDA. Inflammatory markers - IL-6, CRP and NO were significantly increased and confirmed by histopathology. Sub-chronic administration of VCO polyphenols attenuated the Cd-induced biochemical alterations compared to Cd control with remarkably improved histopathological observations.
Conclusion
The findings showed that VCO polyphenol supplementation protects against Cd-induced nephrotoxicity via its antioxidant and anti-inflammatory mechanisms in rats.

Keywords: Polyphenols; Cadmium; Virgin coconut oil; Nephrotoxicity; Oxidative stress; Inflammation

Received: July 11, 2017; Revised: December 24, 2017; Accepted: February 5, 2018; Published: November 1, 2018  Show citation