Protein tyrosine phosphatase 1B inhibitors from a marine-derived fungal strain sp. SF-5929.

In the course of our continuing investigation of bioactive secondary metabolites from marine-derived fungal strains, a racemate of a novel diphenolic derivative named (±)-tylopilusin D () along with ten previously known secondary metabolites () were isolated from a marine-derived fungal strain sp. SF-5929. Their structures were elucidated mainly by analysis of NMR and MS data. In addition, the inhibitory effects of the isolated compounds against protein tyrosine phosphatase 1B (PTP1B) activity were evaluated, and compounds , , and inhibited PTP1B activity with IC values ranging from 3.3 to 8.1 µM. Kinetics studies suggested that compounds , , and had noncompetitive inhibitory effects against PTP1B.