Protective Effect of Santonin Against Doxorubicin Induced Cardiotoxicity via TLR4/NF‐κB, Nrf2/HO‐1, and Caspase‐3 Pathway Modulation in Rats

Doxorubicin (DOX) is a potential chemotherapeutic drug, but its practical use is limited as it causes dose-dependent cardiotoxicity. This study aims to explore the cardioprotective role and mechanism of Santonin (Sant) against doxorubicin-induced cardiotoxicity. Initially, Sant's pharmacokinetics, toxicity, and molecular docking with target proteins were determined computationally. In an in vivo study, Sant pretreatment (30 mg/kg and 60 mg/kg) was administered daily via per oral (PO) route, and cardiotoxicity was induced in rats by a single intraperitoneal (IP) injection of DOX (15 mg/kg). The results revealed that Sant demonstrates favorable pharmacokinetics and low toxicity; therefore, it can be administered orally. Moreover, molecular docking studies revealed a significant interaction of Sant with target proteins. Sant pretreatment significantly recovered DOX-induced neurobehavioral changes, body weight changes, relative heart weight, serum cardiac biomarker levels (LDH, CK-MB, Trop I), serum electrolyte levels (Na⁺, K⁺, Cl^-), and oxidative stress by modulation of antioxidant and oxidative stress markers levels. Sant improved histopathological alterations and cardiac fibrosis. In addition, Sant downregulates inflammatory mediators such as TLR4 and NF-κB, upregulates oxidative stress sensors such as Nrf2 and HO-1, downregulates caspase-3 apoptotic marker, and reverses the DOX-induced DNA damage in cardiac tissue. Sant also decreases the levels of pro-inflammatory cytokines such as TNF-α and IL-1β in DOX-treated rats. This study suggests for the first time that Sant can prove to be the potential therapeutic option for mitigating DOX-induced cardiotoxicity via modulation of inflammatory (TLR4/NF-κB), oxidative stress (Nrf2/HO-1), and apoptotic (Caspase-3) signaling pathways.