Applanmerotic acids A and B, two meroterpenoid dimers with an unprecedented polycyclic skeleton from Ganoderma applanatum that inhibit formyl peptide receptor 2

Two unprecedented Ganoderma meroterpenoid dimers, applanmerotic acids A and B (1 and 2), were isolated from the fruiting bodies of Ganoderma applanatum. Their structures including stereostructures were established by spectroscopic analysis and the quantum chemical calculation (calculated C-13 NMR and electronic circular dichroism) method. Compound 1 was a pair of enantiomers and compound 2 represents the first example of a dimeric meroterpenoid with a 2-oxo-spiro[furo[3,2-b]benzofuran-3,2 '-naphthalene] core. Their plausible biogenetic pathway was proposed, from which their key polycyclic cores were formed through an intermolecular Diels-Alder reaction. Compounds 1 and 2 showed anti-inflammatory activities with IC50 values of 14.5 and 20.9 mu M, respectively, by inhibiting the activation of FPR2 and the further competitive binding assay and molecular docking study indicated their action mechanism.

Automated summary

Two unprecedented Ganoderma meroterpenoid dimers, applanmerotic acids A and B, were isolated from the fruiting bodies of Ganoderma applanatum. These compounds showed anti-inflammatory activities by inhibiting the activation of FPR2, and further studies confirmed their action mechanism.