Abstract
Three new diketopiperazines, dichotocejpins A-C (1-3), together with eight known analogues (4-11), were isolated from the culture of the deep-sea sediment derived fungus Dichotomomyces cejpii FS110. Their structures, including absolute configurations, were elucidated by a combination of HRESIMS, NMR, X-ray crystallography, and ECD calculations. Compounds 4-6, 10-11 showed significant cytotoxic activities against MCF-7, NCI-H460, HepG-2, and SF-268 tumor cell lines. Compound 1 exhibited excellent inhibitory activity against α-glucosidase with an IC50 of 138 μM.