Limonoids from the Stem Bark of Khaya senegalensis

Abstract

Six new limonoids with modified furan ring, khaysenelide A–F (1–6), together with six known limonoids (7–12) were isolated from the stem bark of Khaya senegalensis. The basic skeletons of these new limonoids belong to mexicanolide (1, 2) and rearrangement phragmalin (3–6), which were elucidated on the basis of spectroscopic methods including high resolution-electrospray ionization (HR-ESI)-MS, one and two dimensional (1D and 2D)-NMR and confirmed by single-crystal X-ray crystallography using CuKα radiation of 1 and 3. Their absolute configurations were determined by the X-ray crystallography data and comparison of their electronic circular dichroism spectra. The inhibitory effect on nitric oxide (NO) production in lipopolysaccaride-activated RAW264.7 macrophages of new compounds was also tested.

Graphical Abstract