Mexicanolide and gedunin type limonoids from Khaya senegalensis seeds

Phytochemical investigation of the seeds of Khaya senegalensis (Desr.) A. Juss. led to the isolation of three new mexicanolide-type limonoids (1, 2, 5) and two new gedunin-type limonoids (3, 4), along with five known compounds (6-10). The structures of all new compounds including absolute configuration were unequivocally established by comprehensive spectroscopic analysis, including HRESIMS, 1D/2D NMR and ECD, and those of 1-3 were further confirmed by single-crystal X-ray diffraction analysis. Notably, limonoids 1-4 were identified as rare lactonization derivatives arising from the furan ring, and compounds 6-10 are first reported from this species. Assessment of anti-inflammatory activity using two complementary in vitro models (IL-1β production in LPS-stimulated THP-1 macrophages and NO production in LPS-stimulated RAW264.7 macrophages) indicated that the isolated limonoids (1-10) did not exhibit significant inhibitory activity at 40 μM.