Polyoxygenated 24,28-epoxyergosterols inhibiting the proliferation of glioma cells from sea anemone Anthopleura midori

Eleven sterols (1-11) and one carotenoid (12) were isolated and identified from sea anemone Anthopleura midori. Compounds 1-6 are rare polyoxygenated ergosterols with a 24,28-epoxy moiety. The structures of these epoxyergosterols were determined by NMR and HRESIMS analyses as well as their chemical-physical properties. Epoxyergosterols 1 and 2 were found to be new natural products and 3-6 are new compounds. Bioactive assay showed that compounds 1, 2, 3, 5, 7, 8, 11, and 12 inhibited the proliferation of rat glioma C6 and human glioma U251 cells with IC50 in a range of 2.41-80.45 mu M. Further investigation suggested that 1 and 3 induced apoptosis in glioma cells and 1 blocked U251 cells at the G0/G1 phase. (C) 2014 Elsevier Inc. All rights reserved.