Lamellarins and related pyrrole-derived alkaloids from marine organisms

The isolation, structure determination, biological activities, and synthetic studies of lamellarins and related pyrrole-derived alkaloids including lukianols, polycitrins, polycitones, storniamides, didemnimides, ningalins, and purporone have been summarized. Many of these lamellarins have been isolated from marine organisms, and among these, the ascidian Didemnum is by far the most productive. Purification was accomplished with chromatography on silica gel, Sephadex LH-20, or high performance liquid chromatography. The isolated metabolites were elucidated by nuclear magnetic resonance, HRMS, single-crystal x-ray, and other spectroscopic methods. The structures of lamellarins and related pyrrole-derived alkaloids are related and have a common biogenetic origin and features a pyrrole ring substituted at positions 3 and 4 by polyhydroxy-or methoxyphenyl groups. The aromatic ring is rotationally highly restricted and exists essentially orthogonal to the plane of the pentacyclic ring. These alkaloids possess unique structural features but also exhibit interesting and significant biological properties, including cytotoxicity and antitumor activity, multidrugresistance, HIV-1 integrase inhibition, antibiotic activity, human aldose eductase inhibition, cell division inhibition, immunomodulatory activity, antioxidant activity, and feeding deterrence.