Immunomodulatory Biscembranoids and Assignment of Their Relative and Absolute Configurations: Data Set Modulation in
Peng Sun1, Feng-Yuan Cai1, Gianluigi Lauro2
1Research Centers for Marine Drugs and Pharmaceutical Analysis, School of Pharmacy , Second Military Medical University , 325 Guo-He Road , Shanghai 200433 , People's Republic of China.
Abstract:
Five new biscembranoids, bistrochelides A-E (3-7), were isolated together with glaucumolides A (1) and B (2) from the soft coral Sarcophyton trocheliophorum. Their structures and absolute configurations were determined by spectroscopic methods, X-ray crystal diffraction, and DFT/NMR (density functional theory/nuclear magnetic resonance) and TDDFT/ECD (time-dependent density functional theory/electronic circular dichroism) calculations. A new approach is introduced to determine the relative configuration of a stereocenter through the dynamic evaluation of the mean absolute errors (MAEs) between the investigated diastereoisomers, moving from an "extended" to a more diagnostic "restricted" set of atoms. This research leads to the structure revision of glaucumolides A and B. In in vitro immunomodulatory screening, compounds 1 and 4 significantly induced the proliferation of CD3+ T cells, while compounds 1 and 5 significantly increased the CD4+/CD8+ ratio at 3 μM.
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