Novel citrinin derivatives with enzyme inhibitory activity from the Mariana Trench-derived fungus Penicillium sp. SCSIO 41326.

Four new citrinin derivatives, monankarin G (1), monankarin H (2), penicilliode D (3), and (2S,3S)-2,3,4,6-tetramethyl-2,3-dihydrobenzofuran-5,7-diolone (4), along with nine known compounds (5-13), were obtained from the Mariana Trench-derived fungus Penicillium sp. SCSIO 41326. The accurate structures of new compounds, including absolute configurations were elucidated on the basis of NMR, MS, ECD and Mosher's ester method. All the compounds were evaluated for their enzyme inhibitory activity, the results showed that compounds 2, 4 and 6 exhibited weak acetylcholine esterase (AChE) inhibitory activity and compound 5 exhibited moderate neuraminidase (NA) inhibitory activity with an IC50 value of 87.0 μM.