Antigastritis effects of Armillariella tabescens (Scop.) Sing. and the identification of its anti-inflammatory metabolites

Objectives This study demonstrates the biological and chemical analysis of the mushroom Armillariella tabescens (Scop.) Sing. (Tricholomataceae). Methods Chemical structures of the isolates were determined by 1D and 2D NMR, and ESI-MS, as well as comparison with previously reported data. All isolates were tested for anti-inflammatory effects based on their ability to inhibit LPS-stimulated nitric oxide (NO) production in RAW264.7 cells. Key findings We found that the MeOH extract of the fruiting bodies of A. tabescens showed antigastritis activity against ethanol-induced gastric damage in rats and notably reduced the gastric damage index compared to control in a concentration-dependent manner. Chemical investigation of the MeOH extract led to the isolation of four steroids (1–4), three alkaloids (5–7), two nucleic acids (8–9) and four fatty acids (10–13). This is the first study to report the identification of all isolates, except for compound 7, from A. tabescens. Compounds 1, 2, 3, 4 and 10 showed inhibition on LPS-stimulated NO production. Treatment with compound 10 inhibited expression of iNOS, COX-2, phospho-IKKα, IKKα, phospho-IκBα, IκBα and NF-kappa B in LPS-stimulated RAW264.7 cells. Conclusions Compound 10 likely contributes to the health benefits of A. tabescens as an antigastritis agent through its anti-inflammatory effects.