Molecular Networking Combined with MALDI-MSI Reveals New Lanostane-Type Triterpenoids with Anti-Hepatocellular Carcinoma Activity and Their Spatial Distribution in the Fruit Body of Ganoderma leucocontextum

Guided by the MS/MS metabolome-based molecular networking, 50 compounds, including 18 new triterpenoid metabolites (ganoleucocontins A–R, 1–18), were obtained from Ganoderma leucocontextum. The chemical structures of these novel metabolites were determined based on comprehensive spectroscopic methods and chemical derivation. Compounds 12–15, 17, and 18 represent a new class of triterpenoid dimers linked by 3-hydroxy-3-methylglutaryl (HMG), which were reported for the first time. The cytotoxicity was assessed in Huh7 cells, revealing IC₅₀ values of 24.39–47.29 μM for new compounds 10, 13, 15, 16, and 18. Further studies on the anticancer properties demonstrated that compounds 10 and 15 inhibited tumor cell growth by promoting apoptosis and disrupting the cell cycle. Meanwhile, the mass spectrometry imaging experiments showed that triterpenoids were predominantly distributed at the edge of the upper shell layer in both the cap and stipe, supporting the peels of G. leucocontexum as a main distribution of Ganoderma triterpenoids.