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Penitol A (1), a new citrinin derivative with a rare tricyclic spiro skeleton, was isolated from a coral-derived strain of the fungus Penicillium citrinum. In addition, penicitols E–I (2–6), five new citrinin analogues, were coisolated. Their structures were determined by an analysis of 1D/2D NMR and HRESIMS data, statistical DP4+ analyses based on DFT-GIAO NMR calculations, quantum chemistry ECD calculations, and a single-crystal X-ray diffraction study. The structures of penicitol A (7) and two related synthetic intermediates were revised. Biological evaluation results revealed that penitol A (1) exhibited cytotoxic activity against K562 tumor cells, with an IC50value of 8.8 μM. A proposed route of formation of compounds 1–7was reported.

Four new aranotin-type epipolythiodioxopiperazines, graphiumins K–N (1–4), along with four known analogues (5–8), were isolated from the deep-sea-derived fungus Exophiala mesophilaMCCC 3A00939. Their structures were elucidated by detailed interpretation of NMR and mass spectrometric data. The absolute configuration of the isolates was deduced by a single-crystal X-ray diffraction analysis and the comparisons of experimental electronic circular dichroism (ECD) data with calculated ECD spectra. Graphiumins K (1) and L (2) exhibited cytotoxic activities against the K562, H69AR, and MDA-MB-231 cancer cells with IC50values ranging from 2.3 to 5.9 μM.