Thiazolidinediones are useful antidiabetic medications. However, their use is associated with adverse side effects like edema, heart failure and bone fractures. In this study, we investigated the anti-ferroptosis effects of suberosin (SBR; a prenylated coumarin) in diabetic Sprague Dawley rats. Further, we assessed the effects of co-administration of SBR (30 and 90 mg/kg/day) with thiazolidinedione (TZ at 15 mg/kg) to mitigate TZ-induced cardiomyopathy in diabetic rats. Our results showed that cardiac output, stroke volume, left ventricle systolic and diastolic pressures were aggravated in diabetic rats treated with TZ alone after 4 weeks. TZ treatments induced ferroptosis as well as marked histoarchitecture disarrangements in rat cardiomyocytes. The study found that optimizing volume overload alleviated cardiac hypertrophy and mitigated left ventricular dysfunction in diabetic rats co-treated with SBR. SBR co-administration with TZ reduced MDA levels in heart tissue and serum iron concentration (biomarkers of ferroptosis), downregulated mRNA expressions of LOX, ACSL4, LPCAT3, and promoted GPX4 activity as well as upregulated mRNA levels of AKT/PI3K/GSK3β as compared to the group administered with TZ at 15 mg/kg. SBR co-administration also helped to retain the normal histoarchitecture of cardiomyocytes in diabetic rats. Hence, our results suggested that SBR is an effective supplement and could be prescribed to diabetic patients along with TZ but this requires further clinical trials.