Polyphenol-rich Cucurbita formulation mitigates doxorubicin-induced cardiotoxicity in rats: biochemical, histological, and molecular docking insights

Cardiovascular diseases (CVDs) remained a dominant cause of global mortality, driven in part by oxidative stress and inflammation. Current study set out to evaluate the antioxidant and cardioprotective effects of a polyphenol-rich formulation (PRCF) derived from Cucurbita pepo, Cucurbita moschata, and Cucurbita maxima in 1:1:1 ratio of the formulation. Animals were assembled into five groups: normal control, Doxorubicin-induced cardiotoxicity (DIC, 15 mg/kg intraperitoneal on day 14), positive control (quercetin 10 mg/kg/day orally for the period of 21 days), PRCF-250 and PRCF-500 (polyphenol-rich cucurbits formulation 250 and 500 mg/kg/day respectively). All treatment groups received their respective doses for 21 days and a single DOX dose (15 mg/kg i.p.) on day 14 to induce cardiotoxicity. High-performance liquid chromatography (HPLC) was utilized to analyze and characterize the Polyphenol-Rich Cucurbita Formulation. Additionally, inflammatory biomarkers and oxidative stress indicators were assessed in both in vitro and in vivo models. The HPLC identified 24 polyphenol compounds, with gallic acid (up to 162.69 mg/g extract), resveratrol (6.36 mg/g), and hesperetin (4.96 mg/g) as major constituents. In vitro assays revealed strong antioxidant activity with DPPH IC₅₀ values as low as 6.30 µg/mL (C. pepo extract) and linoleic acid peroxidation inhibition reaching 84.36%. In a doxorubicin-induced cardiotoxicity rat model, oral administration of PRCF (250 and 500 mg/kg/day to DIC group for the period of 21 days) significantly improved lipid profile, atherogenic coefficient (AC), atherogenic index of serum (AIS), and cardiac risk ratio (CRR) and troponin I in dose dependent manners. Treatment of DIC group with PRCF (250 and 500 mg/kg/day) showed statistically significant increase (p ≤ 0.05) in superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and significant decrease (p ≤ 0.05) in malondialdehyde (MDA) in dose dependent manners, supporting the hypothesis that PRCF mitigates doxorubicin-induced oxidative damage. Rats of DIC group had significantly (p ≤ 0.05) increased serum levels of TNF-ɑ, IL-6 and CRP, thus showing the inflammation in the body, when compared with the NC group. All the PRCF treated groups significantly (p ≤ 0.05) reduced the TNF-ɑ, IL-6 and CRP values of all the groups, which demonstrate the protective effect of all cucurbits extracts at both formulation doses. The qPCR analysis showed a significant upregulation (all p ≤ 0.05) of TNF-α and IL-6 mRNA expression in the DIC group, evidenced by substantially lower ΔCt values and corresponding increases in relative gene expression compared to the normal control group. Treatment with both formulation of PRCF (250 and 500 mg/kg/day) significantly down regulated (all p < 0.05) the TNF-α and IL-6 mRNA expressions close to normal group. Similar type of protection was observed by histological evaluation confirmed myocardial protection after 21 days of administrations of PRCF. Molecular docking study predicted strong affinity with the active sites of malonyl coenzyme A ligase with the major compounds present in the formulation. These findings suggest that polyphenol-rich formulation (PRCF) effectively mitigates cardiotoxicity in rats by modulating oxidative, inflammatory pathways in the plasma and molecular levels. Furthermore, molecular docking study prediction for strong affinity of phytoconstituents of formulation with malonyl coenzyme A ligase which is associated with energy pathway in the myocyte supporting its potential as a natural cardioprotective agent.