Abstract
Quince (Cydonia oblonga Mill.) is a pomaceous fruit that is typically processed into jams, jellies, and marmalade. The byproduct, i.e., the quince peel emanated from the processing industry, can be upcycled, ensuring zero waste policy and resulting in a sustainable food system. In our study, the quince peel was explored for in vitro phytochemical analysis and in vivo cardioprotective potential. Two diverse extractions (ultrasonication and reflux) and four different solvents (aqueous, ethanolic, hydroethanolic, and methanolic) were used for the extraction of quince peel and assessed for the phytochemical and antioxidant study. Among all the evaluated extracts, hydroethanolic quince extract extracted through the reflux extraction method showed the maximum phenolic (27.23 ± 0.85 mg GAE/g DW) and flavonoid (16.5 ± 1.02 mg RE/g DW) content. The maximum antioxidant potential (DPPH) with an IC50 value of 204.8 ± 2.24 μg/mL was noted for the hydroethanolic extract. This best active extract was then subjected to HPTLC, UPLC-MS, mineral, and FTIR analysis to study the metabolic profiling and inorganic composition and to confirm the presence of bioactives. Additionally, the in vivo study was done in rats using doxorubicin (DOX)-induced cardiotoxicity. The rats were given extracts orally at 160 and 320 mg/kg bw for 30 days. ECG analysis was done at the termination of the experiment. Besides this, the lipid profile, blood serum parameters (CK-MB, LDH, AST), and tissue parameters (MDA, SOD, GSH, CAT) were analyzed. The DOX-treated group unveiled a substantial variance (p < 0.001) in all the parameters in contrast to the normal control group and extract control groups. However, the pretreated groups substantially alleviated the DOX-induced changes in all the parameters. Additionally, recuperation in histopathological alterations of the cardiac tissue in contrast to the DOX-induced toxicity was also seen in the pretreated groups. Thus, it could be said that the cardioprotective activity of the quince peel extract attributed to the presence of phytoconstituents counteracted the DOX-induced cardiotoxicity and assisted in the restoration of the cardiac injury in rats.