Assessment of the Antidiabetic Effects of Neomarica gracilis Leaf Extract in Streptozotocin-Induced Diabetic Rats: A Biochemical and Histopathological Study

The present study evaluated the antioxidant and antidiabetic activities of the methanolic leaf extract of Neomarica gracilis. Methanolic extraction of 400 g of dried leaves yielded 30.2 g of extract (7.55%). Phytochemical screening confirmed the presence of alkaloids, glycosides, flavonoids, phenolics, carbohydrates, and proteins. The extract exhibited appreciable total phenolic (37.22 mg GAE/g) and flavonoid (23.15 mg RE/g) contents. In the DPPH assay, the extract showed significant antioxidant activity with an IC₅₀ value of 28.81µg/mL, compared with 17.10µg/mL for ascorbic acid. Acute oral toxicity studies indicated that the extract was safe up to 2000 mg/kg body weight, with no mortality observed. In streptozotocin-induced diabetic rats, the extract significantly reduced blood glucose levels and improved the lipid profile in a dose-dependent manner. The 400 mg/kg dose showed greater efficacy, reducing blood glucose to 96.79 ± 0.36 mg/dL by day 21, comparable to Metformin (92.80 ± 0.095 mg/dL). Histopathological findings also demonstrated protection and restoration of pancreatic tissue architecture. These findings suggest that the methanolic leaf extract of Neomarica Gracilis possesses significant antioxidant and antidiabetic activities and may be a promising natural agent for the management of diabetes mellitus.