Calamusins J-K: new anti-angiogenic sesquiterpenes from <i>Sarcophyton glaucum</i>

Abstract

Chemical investigation of the organic extract of the marine soft coral <i>Sarcophyton glaucum</i> from Red Sea, Egypt, afforded two new hydroazulenes; calamusin J (<b>1</b>) and its hydroperoxide derivative calamusin K (<b>2</b>) in addition to eight known compounds. Structure of compounds <b>1-2</b> were confirmed by intensive NMR and mass spectrometry studies. The coral extract and the obtained compounds were examined against a set of diverse microorganisms. The <i>in vitro</i> anti-cancer properties were assessed against colon (Caco-2) and breast (MCF-7) cell lines together with their exerted cytotoxicity on the immortalized normal epithelium (hTERT-RPE1) cell type. The anti-angiogenic power was also highlighted through suppressing MCF-7 cell migration and the significant inactivation of VEGFR2 enzyme. Compounds <b>1,2</b> are the most potent angiogenic inhibitors (represented by 1.2- and 1.4-fold enzyme inactivation, respectively) relative to sorafenib. The polyhydroxy sterol; 5<i>α</i>-3<i>β</i>,6<i>α</i>,11-trihydroxy-24-methyl-9,11-seco-5a-cholest-7-en-9-one (<b>S4</b>) inhibited effectively the growth of Caco-2 and MCF-7 with GI₅₀ of 0.62 and 2.3 µM, respectively.