Despite the widespread use of Grossamide-containing plants in traditional medicine and its documented anti-inflammatory and metabolic regulatory properties, this lignanamide's potential as an antidiabetic agent remains unexplored. Current α-glucosidase inhibitors like acarbose suffer from poor patient compliance due to severe gastrointestinal side effects, creating an urgent need for better-tolerated alternatives. This study investigated whether Grossamide’s unique structural features and established bioactivities could translate into clinically relevant carbohydrase inhibition. Through integrated computational and experimental approaches, we demonstrate that Grossamide exhibits potent dual inhibition of α-amylase (IC50: 44.4 ± 5 μM) and α-glucosidase (IC50: 72 ± 5 μM), showing 50% and 33% lower IC₅₀ values than acarbose (89 and 108 μM, respectively) and comparing favorably to natural inhibitors like quercetin (> 200 μM) while approaching potencies of semi-synthetic derivatives, though not reaching synthetic drug levels (0.2–1 μM). Molecular docking revealed distinct binding modes for each enzyme, with preferential α-amylase engagement potentially reducing side effects associated with excessive α-glucosidase inhibition. Extensive molecular dynamics simulations (100 ns) confirmed binding stability and identified a persistent hydrogen bond network with GLN63 (91% occupancy) as critical for α-amylase inhibition, while α-glucosidase binding involved dynamic interactions across multiple subsites. MM/GBSA calculations revealed strong binding affinities driven predominantly by van der Waals forces, contrasting with the electrostatic-dependent binding of current clinical inhibitors. Comprehensive ADMET profiling predicted acceptable drug-likeness despite the compound's large size, with favorable safety parameters supporting therapeutic development. These findings establish Grossamide as a promising scaffold for developing dual-action antidiabetic agents and demonstrate how computational drug design can identify new therapeutic applications for known natural products, potentially accelerating the drug discovery timeline by repurposing compounds with established safety profiles.