Clavipyrrine A, a unique polycyclic nitrogenous meroterpenoid with promising anti-glioma effects isolated from the fungus Clitocybe clavipes.

Clavipyrrine A (1), a novel polycyclic nitrogenous meroterpenoid with a pyrrolo[1,2- a ]imidazole and a 10-membered carbocycle fused with an α,β-epoxy-γ-lactone, was isolated from Clitocybe clavipes , a basidiomycete. X-ray crystallography and spectroscopic analysis were used to fully elucidate its structure. The biosynthetic origin of the pyrrole unit in this nitrogenous meroterpenoid was identified by incorporating 15N-labeled γ-aminobutyric acid. Compound 1 displayed promising anti-glioma activities and induced glioma cell apoptosis through inhibiting the JAK/STAT3 pathway and reinforcing SOCS1/3. [Display omitted] • One polycyclic nitrogenous meroterpenoid was isolated from Clitocybe clavipes. • The pyrrolo[1,2- a ]benziimidazole skeleton was biosynthetically postulated. • Compound 1 displayed promising anti-glioma activities. • Compound 1 induced glioma cell apoptosis through inhibiting JAK/STAT3 pathway. Clavipyrrine A (1), a novel polycyclic nitrogenous meroterpenoid with a pyrrolo[1,2- a ]imidazole and a 10-membered carbocycle fused with an α,β-epoxy-γ-lactone, was isolated from Clitocybe clavipes , a basidiomycete. X-ray crystallography and spectroscopic analysis were used to fully elucidate its structure. The biosynthetic origin of the pyrrole unit in this nitrogenous meroterpenoid was identified by incorporating 15N-labeled γ-aminobutyric acid. Compound 1 displayed promising anti-glioma activities and induced glioma cell apoptosis through inhibiting the JAK/STAT3 pathway and reinforcing SOCS1/3. [ABSTRACT FROM AUTHOR]