Comparison of Quercetin and Isoquercitrin’s Anti-Heart Failure Activity via MAPK Inflammatory Pathway and Caspase Apoptosis Pathway

<b>Background</b>: Abnormal activation of Angiotensin II (Ang II) serves as a primary trigger for myocardial hypertrophy and cardiac injury. Isoquercitrin (IQ) and Quercetin (Que) possess anti-inflammatory and anti-apoptotic properties, but their protective effects against Ang II-induced cardiac injury remain unclear. This study aimed to investigate the mechanisms and therapeutic efficacy of IQ and Que in heart failure. <b>Methods</b>: Cytotoxic effects of IQ and Que on Ang II-induced H9c2 rat cardiomyocyte apoptosis models were assessed in vitro using the CCK-8 assay. Reactive Oxygen Species (ROS) generation and apoptotic fluorescence levels were measured. WB analysis examined protein expression in inflammatory and apoptotic pathways. In vivo heart failure model was established in mice, with cardioprotective effects of IQ and Que evaluated via echocardiography. Molecular docking was employed to analyze ligand-target interactions. <b>Results</b>: IQ outperformed Que in promoting cell viability and decreasing ROS. IQ exhibited a more potent inhibitory effect on apoptosis through regulating Bax, Caspase-3, CytoC, and Bcl-2 and demonstrated superior suppression of cardiac inflammation by inhibiting phosphorylation of ERK, JNK, and P38. Compared with Que, IQ more effectively attenuated Ang II-induced cardiac injury by ameliorating reductions in EF% and FS%, suppressing ST-segment elevation, and significantly reducing serum levels of CK-MB, LDH, ANP, BNP, and FFA in a heart failure model. Molecular docking verified stronger binding affinity of IQ for key targets. <b>Conclusions</b>: IQ demonstrates superior cardioprotection over Que by regulating MAPK signaling and mitochondrial apoptosis pathways, supporting its potential as a therapeutic candidate for heart failure.