Three new shikimate-conjugated meroterpenoids from Alternaria alternata isolated from an entomopathogenic fungus Apis mellifera

Three new shikimate-conjugated meroterpenes, tricycloalternarenes Z1-Z3 (1-3), were isolated from Alternaria alternate, an endophytic fungus residing in Apis mellifera. The structures of new compounds were characterized by analyses of their NMR and HRESIMS data. The absolute configurations were assigned through electronic circular dichroism (ECD) calculations and CD spectra. Bioassay results showed that tricycloalternarene Z1 (1) exhibited moderate anti-inflammatory activity against the LPS-induced production of NO in RAW 264.7 cells, with an IC₅₀ value of 0.93 µM.