Luotonin A, a novel pyrroloquinazolinoquinoline alkaloid isolated from the aerial parts of Peganum nigellastrum Bunge, showed a cytotoxic activity against mouse leukemia cells (P-388) and an inhibitory activity against topoisomerase I and II. This review covers the isolation, structural determination, synthesis and biological activity of luotonin A and its related derivatives. A water-soluble topoisomerase I inhibitor, 14-azacamptothecin analogous to luotonin A and camptothecin, was also discussed. © 2005 The Japan Institute of Heterocyclic Chemistry All rights reserved.