Ceratinadins E and F, New Bromotyrosine Alkaloids from an Okinawan Marine Sponge <i>Pseudoceratina</i> sp.

• Main Authors: Shin-ichiro Kurimoto, Taito Ohno, Rei Hokari, Aki Ishiyama, Masato Iwatsuki, Satoshi Ōmura, Jun’ichi Kobayashi, Takaaki Kubota
• Format: Article
• Language: English
• Published: MDPI AG 2018-11-01
• Series: Marine Drugs
• Subjects: marine sponge; <i>Pseudoceratina</i> sp.; bromotyrosine alkaloid; ceratinadin; 1,6-dioxa-2-azaspiro[4.6]undecane; 3,5-dibromotyramine; psammaplysin; moloka’iamine; antimalarial activity; <i>Plasmodium falciparum</i>
• Online Access: https://www.mdpi.com/1660-3397/16/12/463

Two new bromotyrosine alkaloids, ceratinadins E (<b>1</b>) and F (<b>2</b>), were isolated from an Okinawan marine sponge <i>Pseudoceratina</i> sp. as well as a known bromotyrosine alkaloid, psammaplysin F (<b>3</b>). The gross structures of <b>1</b> and <b>2</b> were elucidated on the basis of spectroscopic data. The absolute configurations of <b>1</b> and <b>2</b> were assigned by comparison of the NMR and ECD data with those of a known related bromotyrosine alkaloid, psammaplysin A (<b>4</b>). Ceratinadins E (<b>1</b>) and F (<b>2</b>) are new bromotyrosine alkaloids possessing an 8,10-dibromo-9-methoxy-1,6-dioxa-2-azaspiro[4.6]undeca-2,7,9-trien-4-ol unit with two or three 11-<i>N</i>-methylmoloka&#8217;iamine units connected by carbonyl groups, respectively. Ceratinadin E (<b>1</b>) exhibited antimalarial activities against a drug-resistant and a drug-sensitive strains of <i>Plasmodium falciparum</i> (K1 and FCR3 strains, respectively).