Four new triterpenoids from Ganoderma lucidum inhibit fibroblast-myofibroblast differentiation: Ganolanoid a identified as an ESR1 ligand.

Four previously unreported triterpenoids, ganolanoids A-D (1-4), were isolated from Ganoderma lucidum. Their structures, including relative and absolute configurations, were elucidated by IR, UV, HRESIMS, 1D/2D NMR, and X-ray crystallography. The antifibrotic potential of these compounds was evaluated in a TGF-β1-induced activation model using primary mouse lung fibroblasts (MLFs). Compounds 1-3 significantly suppressed the upregulation of the fibrosis marker α-SMA. To explore the underlying mechanism of the most active compound, ganolanoid A (1), an integrated computational approach combining network pharmacology, molecular docking, and 100-ns molecular dynamics simulations was employed, identifying estrogen receptor 1 (ESR1) as a potential target. Ganolanoid A exhibited strong and stable binding to ESR1 (binding energy: -63.85 kcal/mol). Experimental validation further demonstrated that ganolanoid A reversed TGF-β1-induced dysregulation of ESR1 protein expression. In summary, this study expands the chemical diversity of Ganoderma triterpenoids and reveals an ESR1-mediated mechanism by which ganolanoid A attenuates pulmonary fibrosis and supports its further investigation as a potential antifibrotic agent.