Pharmacognostic, Antidiabetic, and Antioxidant Properties of Mitracarpus scaber Zucc. (Rubiaceae) on Alloxan-Induced Diabetic Rats

Diabetes mellitus is a chronic metabolic disorder characterized by hyperglycemia and oxidative stress. Mitracarpus scaber Zucc. (Rubiaceae), a plant used in African ethnomedicine, was evaluated for its pharmacognostic features, antidiabetic, and antioxidant potential.This study aims at assessing the pharmacognostic parameters, antidiabetic activity, and antioxidant effects of dichloromethane and methanolic extracts of Mitracarpus scaber in alloxan-induced diabetic rats. Plant materials were subjected to macroscopic, microscopic, and chemomicroscopic analyses. Extracts were prepared via cold maceration, and phytochemical screening (qualitative and quantitative) was performed. Antidiabetic activity was evaluated in albino rats (n=30) divided into six groups (n=5/group), with doses of 100, 200, and 400 mg/kg extract compared to glibenclamide (1 mg/kg) and controls. Blood glucose was monitored weekly for 3 weeks. Antioxidant parameters (SOD, CAT, GPx, MDA) were assayed in serum. Macroscopic analysis revealed an erect annual herb (10-50 cm) with scabrous leaves and quadrangular stems. Microscopic features included amphistomatic leaves with higher abaxial stomatal density (45.38±1.47 mm⁻²). Chemomicroscopy confirmed tannins, oils, starch, lignin, and calcium oxalates. Extraction yield was 4.45%. Phytochemicals results were dominated by tannins (975.63±2.23 mg/100g), phenols (925.70±2.09 mg/100g), and alkaloids (665.68±2.45 mg/100g). The 200 mg/kg extract showed the highest glucose inhibition (21.931%), approaching glibenclamide (27.929%). Antioxidant assays at 200 mg/kg revealed elevated SOD (36.692±1.627 U/mg) and GPx (23.951±1.029 U/mg), with reduced MDA (10.256±0.294 mmol/mg). Secondary metabolites, particularly tannins and phenols, underpin Mitracarpus scaber's antidiabetic and antioxidant properties, validating its ethnomedicinal use.