Abstract
Doxorubicin (DOX), although effective as a chemotherapeutic agent, induces significant nephrotoxicity, limiting its clinical application. This study investigated the nephroprotective potential of nobiletin and tangeretin, in comparison with the reference compound silymarin, against DOX-induced acute kidney injury (AKI) in rats. DOX administration significantly increased the kidney-to-body weight ratio (p = 0.0053), elevated serum malondialdehyde (MDA) levels (11.49 ± 1.77 nmol/mL), and decreased serum albumin (ALB) levels (10.23 ± 1.84 mg/mL). These changes were accompanied by upregulation of oxidative (NRF2 and HO-1), apoptotic (CASP3 and PARP1), and inflammatory (TNF-α, IL-1β, IL-6, and NF-κB) gene and protein markers. Treatment with flavonoids significantly reversed these effects. Improvements in ALB, MDA, and histopathological scores were observed in all treatment groups without significant intertreatment differences. Nobiletin notably reduced MDA to 8.12 ± 1.56 nmol/mL and restored ALB to 15.89 ± 1.31 mg/mL (p < 0.01) while also downregulating CASP3, TNF-α, and PARP1 expressions. Histopathological analysis showed that nobiletin provided substantial protection against tubular necrosis, glomerular shrinkage, and interstitial inflammation, achieving damage scores similar to the sham group. Furthermore, nobiletin and silymarin both significantly reduced fibrotic area, whereas tangeretin showed moderate effects. Molecular docking revealed that silymarin had the most favorable binding affinities to targets such as CASP3, TNF-α, and HO-1; however, its poor pharmacokinetic properties (TPSA = 155.14 Å(2)) limited its systemic efficacy. In contrast, nobiletin exhibited superior oral absorption (TPSA < 90 Å(2)) and dual CYP inhibition, contributing to better in vivo performance. The NRF2/HO-1 pathway was moderately activated, with HO-1 protein levels elevated despite reduced mRNA, suggesting post-transcriptional regulation. In conclusion, nobiletin displayed a consistent multilevel protective profile, with notable modulation of key apoptotic and inflammatory markers, while all compounds provided comparable biochemical and histological benefits. These findings support further development of nobiletin as a promising nephroprotective agent in chemotherapeutic settings.