Antimicrobial Isochroman‐Derived Atropo‐diastereomeric Dimers from Penicillium steckii SCISO 41228

A pair of unidentified atropisomeric dimers, penicisteckins G (1) and H (2), and twelve known compounds (3-16) were isolated from the marine coral-derived fungus Penicillium steckii SCISO41228. Their structures including the absolute configuration were determined by HR-ESI-MS, ECD, 1D-, and 2D-NMR spectra. Compounds 1 and 2 exhibited potent antibacterial activity against most pathogenic strains, especially for MASA and Micrococcus luteus, with MIC values of 4.0 μg·mL-1. In addition, compounds 2 and 3 exhibit potent antioxidant activity with IC50 values of 10.76 and 8.66 μg·mL-1, respectively.