Lanostane triterpenoids from mycelia-associated Ganoderma sinense and their anti-inflammatory activity

Seven previously undescribed lanostane triterpenoids, ganoderic acid M1 (1), M2 (2), M3 (3), M4 (4), M5 (5), M6 (6), and M7 (7), together with eight known compounds, were isolated from mycelia of the basidiomycete Ganoderma sinense (Ganodermataceae). The structures of all compounds were elucidated by spectroscopic analysis. The possible biosynthetic pathway of these fifteen triterpenoids was proposed. Some of the compounds were evaluated for their anti-inflammatory activity by measuring the production of nitric oxide (NO), TNF-α, and IL-6 in RAW264.7 macrophage cells induced by lipopolysaccharide. Lanosta-7,9(11),24-trien-3β,15α,22β-triacetoxy-26-oic acid (14) exhibited the strongest inhibition of NO production with an IC50 of 0.6 ± 0.1 μM and completely inhibited the secretion of TNF-α and IL-6 at 10 μM. The structure-activity relationship of the anti-inflammatory activity is discussed.