In Vivo Antidiabetic Efficacy of Ethyl Acetate Fractions Cinnamomum tamala (Buch.-Ham.) T. Nees & C. H. Eberm. and Cinnamomum verum J. Presl in Streptozotocin-Induced Diabetic Rats.

Abstract

Objectives: Diabetes mellitus is a progressive metabolic disorder broadly classified into insulin-deficient (type 1) and insulin-resistant (type 2) forms. Both forms ultimately lead to chronic hyperglycemia and pancreatic dysfunction, posing a major global health burden. Limitations associated with the long-term use of conventional antidiabetic drugs have encouraged investigation of plant-based treatments that may offer safer therapeutic benefits. Although Cinnamon species have traditionally been used to manage metabolic disorders, evidence from solvent-fraction studies demonstrating their antidiabetic efficacy remains limited.

Methods: This study evaluated the antidiabetic activity of ethyl acetate fractions obtained from Cinnamomum tamala (Buch.-Ham.) T. Nees & C. H. Eberm. (CT) leaves and Cinnamomum verum J. Presl (CV) bark in streptozotocin (STZ)-induced diabetic Wistar rats. Acute oral toxicity was assessed according to OECD guideline 423. Diabetic rats were treated with the ethyl acetate fractions at doses of 150 and 200 mg/kg body weight for 28 days, with metformin (100 mg/kg) used as the standard drug. Body weight and fasting blood glucose levels were recorded, and the oral glucose tolerance test (OGTT) and pancreatic histopathology were used to assess antihyperglycemic efficacy and tissue-protective effects.

Results: Both fractions were safe up to 2,000 mg/kg. STZ-induced diabetic rats showed weight loss, hyperglycemia, impaired glucose metabolism, and pancreatic β-cell damage. Treatment with both fractions dose-dependently lowered fasting blood glucose and improved glucose tolerance. Cinnamomum verum at 200 mg/kg showed significant antihyperglycemic activity, although its effect remained lower than that of metformin. Histopathological findings suggested that high-dose ethyl acetate fractions preserved pancreatic structure and β-cell integrity.

Conclusion: The ethyl acetate fractions of Cinnamomum tamala and Cinnamomum verum demonstrated notable antidiabetic effects by improving glycemic control and protecting pancreatic islets in STZ-induced diabetic rats, supporting their traditional use and potential as plant-based therapies.