Bioactive Polyketide Derivatives from the Mangrove-Derived Fungus HJ004

Five new tetralones, daldiniones A-E (-), three new chromones, 7-hydroxy-5-methoxy-2,3-dimethylchromone (), 5-methoxy-2-propylchromone (), and 7-ethyl-8-hydroxy-6-methoxy-2,3-dimethylchromone (), and two new lactones, helicascolides D and E ( and ), together with nine known metabolites (-, -, and -) were isolated from the mangrove-derived fungus HJ004. The structures and absolute configurations of the new compounds were determined by analyzing MS and NMR data and utilizing GIAO based C NMR chemical shift calculations and quantum chemical electronic circular dichroism (ECD) calculations. Compounds , , and showed inhibitory activities against α-glucosidase with IC values of 13, 15, and 16 μM, respectively.