Zoanthamine Alkaloid Derivatives from the Zoantharian Zoanthus vietnamensis with Antimetastatic Activity

A novel compound zoanone A (<b>1</b>), together with eight new alkaloids, 3β,14α-dihydroxy-28-deoxyzoanthenamine (<b>2</b>), 7α-hydroxy-28-deoxyzoanthenamine (<b>3</b>), 3α-hydroxyzoanthenamine (<b>4</b>), 7β-hydroxyzoanthenamine (<b>5</b>), 28α-methoxyzoanthenamine (<b>6</b>), 28α-methoxykuroshine A (<b>7</b>), 30-hydroxykuroshine A (<b>8</b>), and 3β-hydroxy-11-deketo-kuroshine B (<b>9</b>), was isolated from the zoantharian Zoanthus vietnamensis. Their structures were elucidated by the comprehensive analyses of IR, mass spectrometry, NMR, and UV spectroscopic data. The absolute configuration of <b>1</b> was established by single-crystal X-ray crystallographic analysis using Cu Kα radiation. A plausible biosynthetic pathway of <b>1</b> was proposed. Antiangiogenic and antilymphangiogenic activities of the isolated metabolites were tested and evaluated. The results showed that all isolated compounds had weak antimetastatic activity.