| Abstract
| - An examination of organic extracts of four new species of South African latrunculid sponges, Tsitsikammapedunculata, T. favus, Latrunculia bellae, and Strongylodesma algoaensis, yielded 13 known and eightnew pyrroloiminoquinone alkaloids, 3-dihydro-7,8-dehydrodiscorhabdin C (4), 14-bromo-3-dihydro-7,8-dehydrodiscorhabdin C (5), discorhabdin V (6), 14-bromo-1-hydroxydiscorhabdin V (7), tsitsikammamineA N-18 oxime (10), tsitsikammamine B N-18 oxime (11), 1-methoxydiscorhabdin D (12), and 1-aminodiscorhabdin D (13). Standard spectroscopic methods provided the structures of the pyrroloiminoquinonemetabolites, while chiral GC−MS analysis of the acylated ozonolysis products of 21 confirmed thestereochemistry of the l-histidine residue in this compound. The anticancer activity of 20 pyrroloiminoquinone compounds was explored in the HCT-116 cancer cell line screen, and the DNA intercalation ofthe tsitsikammamines, together with their ability to cleave DNA through topoisomerase I inhibition, isdiscussed.
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