Abstract
Diabetes mellitus remains a major public health concern in sub-Saharan Africa, where medicinal plants are widely used as complementary sources of care. This study evaluated the phytochemical composition, antioxidant activity, acute oral toxicity, and antidiabetic potential of extracts from the stem bark of Mangifera indica L. collected in the Republic of Guinea. Six solvents of differing polarity were used for extraction, and the extracts were assessed for phytochemical groups, total phenolic, flavonoid, and tannin contents, and antioxidant activity using DPPH, FRAP, ABTS, and lipid peroxidation inhibition assays. The hydroethanolic extract was selected for acute toxicity testing and in vivo evaluation in streptozotocin-induced diabetic Wistar rats treated for 21 days. Phytochemical screening showed alkaloids, catechic tannins, flavonoids, anthocyanins, leucoanthocyanins, quinone derivatives, triterpenes, steroids, cardiotonic glycosides, saponins, and reducing compounds. The hydroethanolic extract had the highest total phenolic content (58.3 mg GAE/g), flavonoid content (23.8 mg QE/g), and DPPH scavenging activity (65.3%; IC50 = 0.44 mg/mL), while the methanolic extract showed stronger FRAP, ABTS, and lipid peroxidation inhibition activities. No mortality was observed after oral administration of doses up to 5000 mg/kg. In diabetic rats, the hydroethanolic extract reduced blood glucose, triglycerides, total cholesterol, and LDL-cholesterol, and increased HDL-cholesterol in a dose-dependent manner, with the 400 mg/kg dose producing the strongest effect. These findings support further investigation of M. indica stem bark as a source of bioactive compounds.