Nootkatone Counteracts Melamine-Mediated Nephrotoxicity via Modulation of Intermediate Filament Proteins, Oxidative, Inflammatory, and Apoptotic Events.

Background: Nootkatone (NK), a bioactive sesquiterpene ketone, is a major ingredient in grapefruit that has distinguished biological activities. Melamine (MM), a food adulterant, was reported to induce toxic effects including renal disorders. Hence, this protocol was devoted to evaluate the renoprotective impact of NK toward MM-evoked renal damage. Methods: Rats were either exposed to MM (700 mg/kg) or a combination of MM and two doses of NK (5 and 10 mg/kg). Results: The results showed that NK therapy notably decreased the kidney functional parameters, along with KIM-1 and NGAL expressions of MM group. Furthermore, a decrease in MDA and NO levels as well as an elevation in SOD, CAT, GSH, and SOD and NRF2 mRNA expression in the NK group demonstrated NK's ability to enhance the renal antioxidant defense of the MM group. Significant suppression in renal inflammatory markers was achieved by NK via lessening of IL-1β and TNF-α, besides downregulation of NF-κB and IL-1β expressions. NK also downregulated vimentin, nestin, and desmin in the MM group. Additionally, in response to the MM exposure, NK hindered renal apoptosis by decreasing caspase-3 expression and restoring renal histopathological features. Conclusion: These outcomes suggest that NK can be considered as a prospective candidate to guard against MM exposure-mediated renal toxic effects.