New -Santonin Derivatives from and Their Anti-Proliferative Activities against and Human Cancer Cells A549.

Previously, we reported two cytotoxic -santonin-amino acid conjugates isolated from the EtOAc layer of . However, a further phytochemical investigation seems to be required because of the few reports of similar derivatives. In this study, we targeted the 1-BuOH layer, which resulted in the isolation of seven new -santonin derivatives (-) together with ten known compounds (-). The structures of - were elucidated based on spectroscopic methods, including 1D and 2D NMR experiments (H, C, DEPT, COSY, HSQC, and HMBC), IR spectrum, and high-resolution electrospray ionization-mass spectrometry (HR-ESI-MS). The stereochemistry of new compounds was confirmed by NOESY and ECD calculations. All isolated compounds were evaluated by in vitro experiments for their anti-proliferative activities against , human lung cancer cell line A549, and Vero cells. As a result, most of the -santonin derivatives, especially -, showed significant cytotoxicity against with a lower IC than the positive control we used (miltefosine).