Twelve new fungal polyketides, koningiopisins I–P
(1–8) and trichoketides C–F
(9–12), together with six known congeners
(13–18), were isolated from Trichoderma koningiopsis, a rhizosphere fungus obtained
from the medicinal plant Polygonum paleaceum. Their
structures and absolute configurations were established by spectroscopic
analysis, single-crystal X-ray diffraction, the modified Mosher’s
method, chemical derivatization, the octant rule, and 13C NMR and ECD calculations. Compounds 1–5 are tricyclic polyketides possessing an octahydrochromene
framework with a 6,8-dioxabicyclo[3.2.1]octane core. Compounds 7 and 8 contain a unique ketone carbonyl group
at C-7 and differ from other members of this group of compounds with
the ketone carbonyl group at C-1. Compounds 1, 2, and 13 showed inhibitory activity on LPS-induced
BV-2 cells on NO production with IC50 values of 14 ±
1, 3.0 ± 0.5, and 8.9 ± 2.7 μM, respectively.
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