Dietary Carvacrol Attenuates Cyclophosphamide-Induced Neurotoxicity: Implications for Food-Derived Neuroprotection and Molecular Mechanisms

Carvacrol (CRV) is a phenolic monoterpene abundant in culinary herbs such as oregano and thyme and is well known for its potent antioxidant, anti-inflammatory, and neuroprotective properties. This study investigated the ability of CRV to counteract neurotoxicity induced by cyclophosphamide (CP), a widely used antineoplastic agent. Male Wistar albino rats were divided into five groups and received CP and/or CRV treatments. Neurotoxicity and neuroprotection were evaluated through biochemical assays, real-time PCR, histopathological and immunohistochemical analyses, and behavioral testing (Morris Water Maze). CP administration led to significant increases in oxidative stress markers, disruption of antioxidant enzyme activities, upregulation of inflammatory mediators (NF-κB, TNF-α, iNOS), dysregulation of apoptotic regulators (increased Bax and Casp-3, decreased Bcl-2), alterations in autophagy markers (Beclin-1, LC3A, LC3B), and suppression of Notch1/Hes1 signaling. Histopathological analyses revealed neuronal degeneration, vascular hyperemia, and increased GFAP and 8-OHdG expression in brain tissue. CRV treatment, particularly at higher doses, effectively mitigated these biochemical, molecular, and histological alterations. Notably, CRV administration preserved spatial learning and memory function in CP-treated rats, as demonstrated by the Morris Water Maze test, indicating functional neuroprotection. These findings highlight the multifaceted neuroprotective mechanisms of CRV and suggest its potential as a food-derived bioactive compound for development into functional foods or dietary supplements to improve the quality of life for cancer patients undergoing chemotherapy.