Darwinella oxeata

Cyclopheophorbide enol (122) a nonmetalated chlorophyll a derivative was isolated from a New Zealand sponge (Darwinella oxeata) and its structure determined by X-ray measurements (113). Although 132,173-cyclopheophorbide enol (122) was first isolated from natural sources, it had previously been synthesized during a study of ring E enolization of chlorophyll derivatives (114). A new pheophorbide a-related compound named chlorophyllone a (123) was isolated from extracts of the short-necked clam Ruditapes philippinarum (115). Compound 123 exhibits antioxidative activity. 

Terpenes are ubiquitous but sterols are uncommon these are either polyhydroxysterols and sulfated sterols or seco-9(l l)-sterols, but in most cases there is A7 imsatu-ration and more rarely A8(9) and/or A8(14). Nitrogen derivatives are frequent, often chlorinated, and sometimes atypical, such as the free porphyrin of Darwinella oxeata (see below). The chlorine derivatives foimd in the species Dysidea herbacea derive from symbiotic cyanobacteria (Unson and Faulkner, 1993 Unson et al., 1993). A review of the genus Dysidea was published by Venkateswarlu, Ramesh, and Reddy (1998). 

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