A tetramic acid derivative with protein tyrosine phosphatase 1B inhibitory activity and a new nortriterpene glycoside from the Indonesian marine sponge Petrosia sp.

Abstract

During the search for protein tyrosine phosphatase 1B (PTP1B) inhibitors from marine organisms, the known tetramic acid derivative, melophlin C (1), was isolated as an active component together with the new nortriterpenoid saponin, sarasinoside S (2), and three homologues: sarasinosides A1 (3), I1 (4), and J (5), from the Indonesian marine sponge Petrosia sp. The structure of 2 was elucidated on the basis of its spectroscopic data. Compound 1 inhibited PTP1B activity with an IC50 value of 14.6μM, while compounds 2–5 were not active at 15.2–16.0μM. This is the first study to report the inhibitory effects of a tetramic acid derivative on PTP1B activity.