Bioactive Meroterpenoids and Isocoumarins from the Mangrove-Derived Fungus Penicillium sp. TGM112

Two new meroterpenoids, penicianstinoids A and B (1 and 2), and eight new isocoumarins, peniciisocoumarins A–H (3–10), together with 10 known analogues (11–20) were obtained from the mangrove-derived fungus Penicillium sp. TGM112. The structures and absolute configurations of 1–10 were determined by interpretation of detailed NMR, MS spectroscopic data, X-ray diffraction analyses, modified Mosher’s method, and calculated electronic circular dichroism data. Compounds 1–4, 7, 8, 10, 12, 13, and 16 showed growth inhibition activity against newly hatched larvae of Helicoverpa armigera Hubner with IC50 values ranging from 50 to 200 μg/mL, respectively. Compounds 1, 2, and 11–15 displayed activity against Caenorhabditis elegans with EC50 values ranging from 9.4 (± 1.0) to 38.2 (± 0.6) μg/mL, respectively. Compound 1 represents an austinoid-like meroterpenoid that is reported here for the second time, in which a carbon–carbon double bond was oxidized to a carbonyl group at C-1′–C-2′.