Anti-Hyperglycemic and Antioxidant Effects of Sclerocarya birrea Leaf Crude Extract and Biosynthesized Silver Nanoparticles In Vitro

Abstract

Postprandial hyperglycemia represents a critical therapeutic target in type 2 diabetes mellitus (T2DM), requiring interventions that simultaneously address glycemic dysregulation and oxidative stress. This study evaluated the anti-hyperglycemic and antioxidant properties of <i>Sclerocarya birrea</i> leaf crude extract (CE) and biosynthesized silver nanoparticles (AgNPs). Phytochemical screening, nanoparticle characterization (UV-Vis, XRD, TEM, SEM, DLS, FTIR), enzyme inhibition assays (α-amylase, α-glucosidase, DPP-IV), glucose dynamics in Caco-2 cells, and antioxidant assays (DPPH, total antioxidant capacity, H₂O₂ cytoprotection) were performed. Phytochemical analysis identified flavonoids, tannins, alkaloids, and terpenoids as major constituents of <i>Sclerocarya birrea</i> leaf extract. AgNPs exhibited spherical morphology (36.8 ± 8.6 nm, n = 100 particles analyzed), face-centered cubic crystallinity (crystallite size: 32.1 nm), and characteristic surface plasmon resonance at 451 nm. Both formulations inhibited α-amylase (CE IC₅₀: 14 µg/mL; AgNPs IC₅₀: 14.07 µg/mL, n = 3) and α-glucosidase (CE IC₅₀: 15.96 µg/mL; AgNPs IC₅₀: 15.82 µg/mL, n = 3), showing substantial inhibition, though less potent than acarbose. Uniquely, AgNPs demonstrated selective DPP-IV inhibition (IC₅₀: 220.5 µg/mL, n = 3, <i>p</i> < 0.001 vs. CE), completely absent in CE. In antioxidant assays, DPPH scavenging potency was comparable between formulations (CE IC₅₀: 23.45 µg/mL; AgNPs IC₅₀: 22.26 µg/mL, n = 3), while CE achieved higher maximal scavenging at the tested concentrations. Conversely, AgNPs provided superior intracellular cytoprotection against H₂O₂-induced oxidative stress in kidney cells (80.2 ± 2.1% viability at 76 µg/mL vs. CE 69.8 ± 3.4% at 190 µg/mL, n = 3, <i>p</i> < 0.001), representing a 2.5-fold dose advantage. Neither formulation significantly altered glucose uptake or SGLT1 expression in intestinal epithelial cells (<i>p</i> > 0.05, two-way ANOVA, n = 3). These findings establish <i>S. birrea</i>-based formulations, particularly AgNPs, as promising multifunctional candidates for managing postprandial hyperglycemia and oxidative complications in T2DM. They also highlight nanotechnology-enhanced phytomedicine as an innovative therapeutic strategy.