Phragmalin and mexicanolide limonoids with reversal of multidrug resistance from the seeds of Chukrasia tabularis A. Juss.

Six undescribed 1,8,9-phragmalin limonoid orthoesters (chukorthoesters A-F, 1-6) and two undescribed mexicanolide-type limonoids (ivorenoids H and I, 7 and 8), together with ten known limonoids, were isolated from the seeds of common wood-source and greening plants Chukrasia tabularis A. Juss. Their chemical structures were elucidated using HR-ESI-MS, 1D and 2D NMR spectroscopic analysis, and that of 1 along with absolute configuration was confirmed by X-ray diffraction experiment with Cu Kα radiation. Bioactivities screening indicated the limonoid orthoesters 1 and 2 shown reversing resistance in MCF-7/DOX cells at 10 µM (RF:4-5 folds).