Seven new decahydrofluorene-class alkaloids, pyrrospirones
K–Q
(1–7), together with six known analogues
(8–13) were isolated from the marine-derived
fungal strain Penicillium sp. SCSIO 41512. Their
structures were determined by extensive spectroscopic analysis, and
their absolute configurations were established by single-crystal X-ray
diffraction analysis and quantum chemical calculations of electronic
circular dichroism spectra. Compounds 1 and 3 possess a novel decahydrofluorene-class alkaloid skeleton with a
6/5/6/8/5/6/13 and a 6/5/6/5/6/13 polycyclic system, respectively.
Biologically, 13 displayed significant inhibitory activity
against protein tyrosine phosphatases CD45, TCPTP, SHP1, and PTP1B
with IC50 values of 8.1–17.8 μM, and 1, 2, 5, 8–10, 12, and 13 showed antibacterial
activity against six pathogens. Their structure–activity relationship
is also discussed.