Biological Secondary Metabolites from the Lumnitzera littorea-Derived Fungus Penicillium oxalicum HLLG-13

Five new compounds, including two cyclopiane diterpenes conidiogenones J and K ( - ), a steroid andrastin H ( ), an alkaloid ( )-4-(5-acetoxy- -hydroxy-3-methylpent-2-enamido) butanoate ( ), and an aliphatic acid ( )-5-acetoxy-3-methylpent-2-enoic acid ( ), together with ten known compounds ( - and - ) were isolated from the EtOAc extract of the fermentation broth of the -derived fungus HLLG-13. Their structures were elucidated by 1D, 2D NMR, and HR-ESI-MS spectral analyses. The absolute configurations of , , and were determined by quantum chemical electronic circular dichroism (ECD) calculations, and the absolute configuration of was determined for the first time. Compound was a new natural product, and its NMR data were reported for the first time. Compounds and - exhibited antibacterial activities against and , with MIC values ranging from 6.25 to 25 μg/ mL. Compounds - and - showed significant growth inhibition activities against newly hatched Hubner larvae, with IC values ranging from 50 to 200 μg/mL.