Discovery of new marine fungal secondary metabolites with α-glucosidase inhibitory and antibacterial activities via reverse pharmacophore mapping and molecular dynamics.

Diabetic patients are highly susceptible to secondary bacterial infections, highlighting the urgent need for dual-action multi-target-directed ligands (MTDLs) possessing both hypoglycemic and antibacterial efficacies. In this study, two new naturally-produced α-pyrone meroterpenoids asperrpenoids A (1) and B (2), and one new triyclic sesquiterpene lactone asperrpenoid C (3), along with five known α-pyrone meroterpenoids were isolated from the mangrove-derived fungus Aspergillus spinosus. Their structures were elucidated by spectroscopic analyses and ECD calculations. To facilitate biological evaluation, reverse pharmacophore mapping was employed to predict their dual potential against DNA topoisomerases and carbohydrate metabolism-related enzymes. Subsequent in vitro assays showed that compounds 4-6 exhibited α-glucosidase inhibitory activities, with compound 5 displaying the strongest activity (IC50 = 12.53 μM). In antibacterial assays, compound 1 showed potent antibacterial activity against Staphylococcus aureus strains, with MIC values of 1-4 μg/mL. Structure-activity relationship analysis indicated that highly lipophilic acyclic chains favored anti-S. aureus efficacy, whereas polar terminal functionalization enhanced α-glucosidase inhibitory activity. Among the isolated compounds, compound 6 with an acetylated monocyclic terminus achieved an apparent physicochemical balance as a promising MTDL, which exhibited both mixed-type α-glucosidase inhibitory efficacy and moderate antibacterial activity. The atomistic binding mechanisms were further elucidated via molecular docking against α-glucosidase and the predicted bacterial targets (DNA gyrase and DHFR). Furthermore, 100 ns molecular dynamics (MD) simulations thermodynamically validated the temporal stability of these target complexes. These findings provide a computationally guided pharmacological strategy for the rational discovery of dual-action therapeutics and identify 6 as a promising MTDL for combating diabetic infectious complications.