Six new 4-phenyl-3,4-dihydroquinolone derivatives (1-6) along with the related aflaquinolone A (7) were isolated and identified from the cultures of Aspergillus nidulans MA-143, an endophytic fungus obtained from the fresh leaves of the marine mangrove plant Rhizophora stylosa. Their structures including absolute configurations were determined by spectroscopic analysis and electronic circular dichroism experiments, and the structure of compound 1 was confirmed by single-crystal X-ray crystallographic analysis. In bioscreening experiments, none of the isolated compounds showed potent antibacterial or cytotoxic activity. However, compounds 2, 3, and 7 exhibited lethality against brine shrimp (Artemia salina), with LD50 values of 7.1, 4.5, and 5.5 μM, respectively.

A novel triazole carboxylic acid, penipanoid A (1), two new quinazolinone alkaloids, penipanoids B (2) and C (3), and a very recently reported quinazolinone derivative (4) were isolated from the marine sediment-derived fungus Penicillium paneum SD-44. Their structures were elucidated by spectroscopic analysis, and the structure for 1 was confirmed by X-ray crystallographic analysis. Compound 1 represents the first example of a triazole derivative from marine sediment-derived fungi, and compound 2 is a rare quinazolinone derivative having a dihydroimidazole ring system. The cytotoxicity of compounds 1 and 4 and the antimicrobial activity of 1-4 were evaluated.