Swieteliacates S-U, phragmalin limonoids, from the leaves of Swietenia macrophylla

Three novel phragmalin-type limonoids, swieteliacates S-U (1-3), were isolated from Swietenia macrophylla leaves, alongside four previously identified limonoids (4-7). The structures, encompassing absolute configurations, were delineated through 1D and 2D NMR analyses, high-resolution mass spectrometry (HR-MS), and NMR and ECD calculations. Swieteliacate S (1) is a distinctive cryptate comprising a tricyclo[4.2.1(10,30).1(1,4)]decane fragment and an additional five-membered oxygen ring. Compounds 3 and 5 exhibited inhibition rates of 26.08 +/- 2.26% and 15.42 +/- 3.66%, respectively, on triglyceride (TG) production in Hep G2 cells at 40 mu M.