Cyclopiazonic Acid and Okaramine Analogues, Including Chlorinated Compounds, from Chrysosporium undulatum YT-1.

Abstract

Eight new cyclopiazonic acid (1-8) and five new okaramine (9-13) alkaloids together with 13 known compounds were isolated from the fungus Chrysosporium undulatum YT-1. Compounds 2, 4, 5, 7, 10, 11, and 13 were chlorinated indole alkaloids. The structures of compounds 1-13 were elucidated by HRESIMS and NMR spectroscopic data. Their relative and absolute configurations were established by J-based configuration analysis, NOESY, NOEDIFF experiments, ECD spectroscopic data, and biogenetic considerations. Compound 4 inhibited the growth of Bacillus subtilis with an MIC value of 6.3 μg/mL. Compounds 9-11 exhibited strong insecticidal capacity against the third instar larvae of silkworm and cotton bollworm (LD50: ≤7.56 μg/g). At 40 μM, compound 1 showed obvious neuroprotection to the PC12 cells with 6-OHDA treatment.