Cassia fistula L. Fruit Extract Attenuates Renal and Cardiac Toxicities by Reducing Oxidative Stress and Inflammation in Fludrocortisone Acetate‐Treated Long Evans Rats

Renal and cardiovascular diseases are major contributors to death worldwide. We investigated the therapeutic effect of Cassia fistula fruit extract (CFFE) on fludrocortisone acetate (FCA)–induced oxidative stress, renal toxicity, and cardiac fibrosis in rats. Long Evans rats were divided into different treatment groups, and biochemical tests were conducted on plasma, kidney, and heart homogenates to measure oxidative/antioxidative parameters and organ‐specific functional markers. The expression of proinflammatory and fibrotic genes in cardiac tissue was also measured. We observed that CFFE administration reduced the elevated levels of oxidative stress markers—malondialdehyde (MDA) and advanced oxidative protein products (AOPPs)—while enhancing the reduced antioxidant enzyme levels of catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH) in FCA‐treated rats. Similarly, the CFFE treatment significantly reduced the increased plasma levels of cardiac troponin I (cTnI), uric acid, and creatinine in these rats. There was elevated expression of IL‐1β, IL‐6, TGF‐β1, and TNF‐α genes in the heart of the FCA rats, which was substantially downregulated by CFFE treatment. Histological investigations further revealed morphological abnormalities and fibrosis in the kidney and heart of the FCA rats, while CFFE treatment markedly ameliorated these signs. Our results suggest that CFFE prevents FCA‐induced oxidative stress, renal injury, and associated cardiac damage and fibrosis by enhancing the antioxidant defense system and controlling inflammation.