ABSTRACT
Within the last 35 years, research into marine natural products chemistry has yielded a stunning array of novel secondary metabolites, often with interesting and useful biological activity. Researchers have primarily fo cused on marine invertebrates, and certain phyla, such as the Porifera or sponges, have received considerably more attention than others. The phy lum Bryozoa has been comparatively little studied, partly through diffi culties in obtaining sufficient quantities of material for research purposes, but also partly through a lack of familiarity with the phylum. Most peo ple, scientist and layperson alike, have either never heard of a bryozoan, or if they have, would certainly have great difficulty in recognizing one. The first and only comprehensive survey of bryozoan secondary metabolites was published in 1985 (Christophersen 1985a) and continu ing annual reviews of all marine natural products are published in Natu ral Product Reports (Faulkner 1984a, 1984b, 1986-1988, 1990-2000). Marine alkaloids in general have been reviewed several times (Christophersen 1985b, Fenical 1986, Bhakuni 1994, Proksch et al. 1998) with some reviews focusing on bioactive alkaloids (Bhakuni 1994) or their ecological signifi cance (Proksch et al. 1998). As the total number of secondary metabolites isolated from bryozoans is small compared with that from many other marine phyla, this review deals with all the literature published on this subject up until August 2000. Alkaloids have been isolated from fifteen species of bryozoans and many of these alkaloids contain novel ring systems. Some of the alkaloids may be of bacterial origin.
