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

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 (LD 50 : ≤7.56 μg/g). At 40 μM, compound 1 showed obvious neuroprotection to the PC12 cells with 6-OHDA treatment.