Ganolearic Acid A, a Hexanorlanostane Triterpenoid with a 3/5/6/5-Fused Tetracyclic Skeleton from Ganoderma cochlear

Ganolearic acid A (1), a 3,4-seco-hexanortriterpenoid featuring a rare 3/5/6/5 tetracyclic system, was obtained in trace amounts from Ganoderma cochlear by a LC-UV/MS-guided method. Meanwhile, a new 3,4-seco-nortriterpenoid, fornicatin M (2), as well as its biogenetic precursor, fornicatin D (3), was isolated. The stereochemical structure of 1 was completely established by 1D, 2D NMR, IR, and HRMS spectra, as well as 13C NMR and electronic circular dichroism calculations. The plausible biogenetic pathway of 1 and 2 was proposed. Furthermore, their anti-inflammatory activities were evaluated.