5-Alkylpyrrole-2-carboxaldehyde derivatives from the Chinese sponge Mycale lissochela and their PTP1B inhibitory activities

Two new 5-alkylpyrrole-2-carboxaldehyde derivatives, mycalenitrile-15 (1) and mycalenitrile-16 (2), along with five known related ones (3-7), were isolated from the South China Sea sponge Mycale lissochela. The structures of the new compounds were elucidated on the basis of extensive spectroscopic analysis and by comparison of their NMR data with those reported in the literature. In bioassay, compounds 1 and 7 exhibited significant PTP1B (Protein-tyrosine phosphatase 1B, a recognized target for diabetes and obesity) inhibitory activities with IC₅₀ values of 8.6 and 3.1 μmol/L, respectively. A preliminary SAR analysis of the isolated compounds with their PTP1B inhibitory effects was described.