The Cardioprotective Potential of Red Onion Waste Against Isoprenaline-Induced Myocardial Infarction in Rat: Molecular Docking and In Vivo Studies.

This study investigated the cardioprotective potential of red onion scales, an underutilized agro-food waste and potential source of value-added bioactive compounds, against isoprenaline (ISO)-induced myocardial infarction (MI) in rats. Bioactive phytoconstituents were extracted using acidified ethanol, yielding a phenolic-rich extract with promising antioxidant activity. Male Wistar rats (n = 8/group) were divided into saline control, extract control (300 mg/kg), ISO (65 mg/kg, s.c., days 29-30), and ISO plus red onion scale extract at 150 or 300 mg/kg for 30 days. Cardiac injury and associated oxidative, inflammatory, and endoplasmic reticulum stress responses were assessed by electrocardiography, echocardiography, serum assays, ELISA, RT-qPCR, and immunohistochemistry. ISO increased QRS and QTc intervals, CK-MB, and cTn-T, while reducing ejection fraction (EF). The extract attenuated these alterations, reduced malondialdehyde, enhanced Nrf2 and SOD, and suppressed of inflammation (NF-κB, IL-1β, and CHOP/ATF4) signaling. Exploratory molecular docking predicted interactions of extract compounds (quercetin, spiraeoside, cyanidin-3-O-glucoside) within the active site of myeloperoxidase enzyme (PDB: 4C1M), providing hypothesis-generating evidence for potential molecular interactions rather than experimental confirmation of mechanism. Overall, the findings point out the red onion scales as an effective and sustainable cardioprotective agent with a novel perspective on an interaction in MI treatment using a multi-mechanistic approach.