Phytochemical Investigation of Gyrinops vidalii Leaves and Evaluation of the α-Glucosidase Inhibitory Activity of the Isolated Metabolites and Molecular Docking of the Active Compounds

Gyrinops vidalii (Thymelaeaceae), a critically endangered agarwood-producing species native to Thailand and Laos and remains phytochemically unexplored. In this study, the chemical constituents and biological activities of the ethyl acetate (EtOAc) fraction of methanol extract of G. vidalii leaves were investigated. Phytochemical analysis led the isolation of mangiferin (1), iriflophenone 3-C-β-D-glucoside (2), aquilarinenside E (3), iriflophenone 2-O-α-L-rhamnoside (4), 5,7,4′-trimethoxyflavone (5), blumenol A (6), loliolide (7), 4-hydroxybenzoic acid methyl ester (8), and 4-hydroxybenzoic acid (9). Compound 1 exhibited potent DPPH radical scavenging activity with an SC50 value of 19.35 μM), whereas iriflophenone (3a), obtained by acid hydrolysis of 3, and 5 showed promising α-glucosidase inhibitory activity with IC50 values 100.06 and 174.57 μM, respectively. Molecular docking demonstrated favorable binding of both compounds within the α-glucosidase active site through hydrogen bonding, aromatic, and hydrophobic interactions, with binding energies of −7.4 and −8.0 kcal/mol, respectively. Predicted ADMET properties further supported the drug-like potential of both compounds, indicating favorable aqueous solubility, high intestinal absorption, and no predicted hepatotoxicity, while differences were observed in their predicted blood–brain barrier permeability. This study represents the first phytochemical investigation of G. vidalii, provides scientific support for its traditional use, and expands the chemotaxonomic knowledge of the closely related genera Gyrinops and Aquilaria.