Thaixylomolins O-R: four new limonoids from the Trang mangrove, Xylocarpus moluccensisElectronic supplementary information (ESI) available: Fig. S1-S3, 1D and 2D NMR spectra for 1-4, and X-ray crystallographic data of 1 and 3. CCDC 1483637 and 1483638. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6ra14721f

• Main Authors: Dai, Yi-Guo, Li, Wan-Shan, Pedpradab, Patchara, Liu, Jun-Jun, Wu, Jun, Shen, Li
• Format: Article
• Language: English
• ISSN: 2046-2069
• DOI: 10.1039/c6ra14721f

Two novel phragmalin 8,9,12-orthoesters, named thaixylomolins O-P ( 1-2 ), a 9,10- seco mexicanolide with a unique trans -orientation of H5 and Me-19, named thaixylomolin Q ( 3 ), and the first secomahoganin-type 7-nor-limonoid with a 6-oxabicyclo[3.2.1]octan-3-one motif, named thaixylomolin R ( 4 ), were isolated from the seeds of a Thai mangrove, Xylocarpus moluccensis collected from the mangrove swamps of the Trang Province. The absolute configurations of these limonoids were unambiguously determined by HRESIMS, extensive NMR investigations, single-crystal X-ray diffraction analyses with Cu Kα radiation, and quantum-chemical electronic circular dichroism (ECD) calculations. Most notably, thaixylomolins O-P are unusual phragmalins with a 8,9,12-orthoacetate group reported for the second time. Thaixylomolin P exhibited antitumor activities against ovarian A2780 and A2780/T cells with an equal IC 50 value of 37.5 μM. Four new limonoids, including two novel phragmalin 8,9,12-orthoesters, were identified from the seeds of Thai mangrove, Xylocarpus moluccensis .