Antioxidant metabolites from the endophytic fungus Aspergillus spelaeus

Five undescribed compounds, including two drimane-type sesquiterpenoids, asperdrimanes A and B ( 1 and 2 ), and three amide compounds, asperspamides A–C ( 3 – 5 ), together with four known metabolites 6 – 9 , were isolated from the fungus Aspergillus spelaeus GDGJ-286. By extensively analyzing NMR, LC–MS/MS, Marfey's method, and X-ray crystallography, the structures were characterized successfully. Asperdrimanes A and B ( 1 and 2 ) are drimane-type sesquiterpenoids characterized by a spiro- β -lactone moiety. Asperspamide B ( 4 ) exhibited exceptional antioxidant capacity in ABTS, FRAP, and DPPH tests, along with significant neuroprotective effects in a hydrogen peroxide-induced PC12 cell oxidative injury model, demonstrating strong anti-apoptotic and anti-necrotic properties. These findings highlight asperspamide B’s potential as a lead compound for developing antioxidant agents.