Cytotoxic limonoids from Melia azedarach.

Five new compounds (1-5), including two limonoids, one triterpenoid, one steroid, and one sesquiterpenoid, along with nine known limonoids (6-14), were isolated from the bark of Melia azedarach. The structures of the new compounds were elucidated by 2D NMR spectroscopy and mass spectrometry. The isolated compounds as well as three acetylated derivatives of 9 were evaluated for their cytotoxicities against five human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW480) by an MTT assay. Seven limonoids (1, 6, 7, 8, 9, 9b, and 9c) showed significant inhibitory activities against tested cell lines with IC50 values ranging from 0.003 to 0.555 µM, and their preliminary structure-activity relationships are also discussed.
(Georg Thieme Verlag KG Stuttgart · New York.)