Red and White Grape Pomace Possess Cardioprotective Effects by Modulating Inflammation and Oxidative Stress in Experimental Ischemic Heart Disease

Background: Cardiac ischemia (CI) remains a leading cause of death worldwide, prompting an ongoing search for new treatment options. This study explored and compared the preventive cardioprotective effects of polyphenols extracted from red (RGP) and white grape pomace (WGP) against isoproterenol (ISO)-induced myocardial ischemia, with a focus on their antioxidant and anti-inflammatory properties. Materials and Methods: Fifty male Wistar rats were divided into five groups: I—Saline, II—Saline+ISO, III—Ramipril+ISO, IV—WGP+ISO, and V—RGP+ISO. CI was induced in Groups II–V with ISO (45 mg/kg, on day 13), a dose widely used to reproducibly induce myocardial ischemic injury in experimental models. Electrocardiographic parameters, serum oxidative markers, cytokines, and tissue homogenates from the liver and heart were analyzed on day 14. Results: ISO significantly shortened the RR interval and increased the ventricular rate, without significant modulation by any treatment. The reduction in R-wave amplitude caused by ISO was lessened in all treated groups, with RGP showing values closer to Saline (RGP+ISO vs. Saline, p = 0.329). No differences were found among groups for PR segment, QRS duration, QT, or QTc intervals. Furthermore, all treated groups (III–V) showed significant improvements in oxidative and inflammatory markers compared to Saline+ISO (p < 0.05), with RGP demonstrating the strongest antioxidant activity by maintaining MDA and NO levels close to Saline (RGP+ISO vs. Saline, p > 0.05), while WGP exhibited superior anti-inflammatory effects in cardiac tissue by preserving IL-6 and IL-1β levels comparable to controls (WGP+ISO vs. Saline, p > 0.05). Conclusions: Grape pomace, especially RGP, may offer cardioprotection by decreasing oxidative stress, while WGP more effectively reduces inflammation. The complementary antioxidant and anti-inflammatory effects observed suggest that combining GP extracts may represent a promising hypothesis for future cardiovascular research.