Background/Objectives: In the search for potent non-sugar α-glucosidase inhibitors with improved safety profiles, a novel flavonoid glycoside was isolated for the first time from the stem bark of Albizia saponaria (Fabaceae). The objective of this study was to elucidate its chemical structure and evaluate its therapeutic potential as an anti-hyperglycemic agent compared to known related flavonoids and a standard clinical drug. Methods: Comprehensive structural elucidation was performed using high-resolution mass spectrometry and multidimensional 1D/2D NMR (1H, 13C, HSQC-DEPT, COSY, and CIGAR). To assess its inhibitory efficacy and pharmacokinetic profiles, an in silico comparative study was conducted against a database of related flavonoids (Quercitrin, Hyperoside, and Isoquercitrin) and the clinical drug Acarbose. This involved molecular docking simulations against human intestinal maltase-glucoamylase (PDB ID: 3TOP) alongside integrated ADMET modeling and toxicological screening. Results: The compound was successfully identified as 4′,7-dihydroxyflavan-3′-O-β-D-glucoside (1). Molecular docking revealed that Compound 1 exhibited a superior predicted binding affinity of −9.5 kcal/mol, outperforming Quercitrin (−9.3 kcal/mol), Hyperoside (−8.3 kcal/mol), Isoquercitrin (−7.9 kcal/mol), and Acarbose (−7.2 kcal/mol). This strong thermodynamic stability is driven by a robust conventional hydrogen-bonding network with key active site residues (Arg1377, Gln1372, and Gly1365), successfully overriding a localized electrostatic strain at Asp1279. Furthermore, ADMET modeling demonstrated a highly desirable local pharmacokinetic framework; its low Caco-2 permeability (−6.432) and low human intestinal absorption (HIA = 0.120) favor targeted luminal retention in the gastrointestinal tract, mirroring Acarbose while minimizing systemic exposure. Crucially, toxicological screening unveiled a significant safety advantage for Compound 1, marked by negligible CYP3A4 interaction (0.004) and a remarkably low risk of Drug-Induced Liver Injury (DILI = 0.213) compared to the high-risk hepatotoxic profile of Acarbose (DILI = 0.882) and the reference flavonoids (DILI > 0.69). Conclusions: These predictive findings establish Compound 1 as a highly promising, low-toxicity natural scaffold for anti-hyperglycemic drug development. Its superior binding affinity and minimized hepatotoxicity risk warrant subsequent in vitro and in vivo functional validation.