Three New Indole Diketopiperazine Alkaloids from Aspergillus ochraceus

Asperochramides A - D (1 - 4), a new natural product and three new indole diketopiperazine alkaloids, along with seven known analogs (5 - 11), were isolated from the ethyl acetate extract of Aspergillus ochraceus. Their structures were elucidated by extensive spectroscopic analyses, ECD calculation, and single-crystal X-ray diffraction analysis. Compounds 3 and 4 represent a rare group of indole diketopiperazine alkaloid with a 3-hydroxyl-2-indolone moiety. The in vitro anti-inflammatory effects of compounds 1 and 3 - 11 were investigated by using LPS-stimulated murine macrophage RAW 264.7 cells. Compounds 1, 8, 10, and 11 showed potential anti-inflammatory activities.