Frondoplysins A and B, Unprecedented Terpene-Alkaloid Bioconjugates from Dysidea frondosa

The chemical investigation of the marine sponge Dysidea frondosa discovered a pair of unprecedented bioconjugates that are composed of a meroterpene and an unusual psammaplysin alkaloid. The structures of frondoplysins A (1) and B (2) were characterized by analysis of HRMS and NMR data coupled with single-crystal X-ray diffraction. Frondoplysin A was found to be a potent inhibitor targeting protein-tyrosine phosphatase 1B (PTP1B) with an IC50 value of 0.39 μM.