Marine cyanobacteria—a prolific source of natural products

Cyanobacteria produce a large number of compounds with varying bioactivities. Prominent among these are toxins: hepatotoxins such as microcystins and nodularins and neurotoxins such as anatoxins and saxitoxins. Cytotoxicity to tumor cells has been demonstrated for other cyanobacterial products, including 9-deazaadenosine, dolastatin 13 and analogs. A number of compounds in cyanobacteria are inhibitors of proteases — micropeptins, cyanopeptolins, oscillapeptin, microviridin, aeruginosins- and other enzymes, while still other compounds have no recognized biological activities. In general cyclic peptides and depsipeptides are the most common structural types, but a wide variety of other types are also found: linear peptides, guanidines, phosphonates, purines and macrolides. The close similarity or identity in structures between cyanobacterial products and compounds isolated from sponges, tunicates and other marine invertebrates suggests the latter compounds may be derived from dietary or symbiotic blue-green algae.

Bioactive compounds produced by cyanobacteria

Nonanomeric spiroketals in natural products: structures, sources, and synthetic strategies.

Cyanobacteria produce an unparalleled variety of toxins that can cause severe health problems or even death in humans, and wild or domestic animals. In the last decade, biosynthetic pathways have been assigned to the majority of the known toxin families. This review summarizes current knowledge about the enzymatic basis for the production of the hepatotoxins microcystin and nodularin, the cytotoxin cylindrospermopsin, the neurotoxins anatoxin and saxitoxin, and the dermatotoxin lyngbyatoxin. Elucidation of the biosynthetic pathways of the toxins has paved the way for the development of molecular techniques for the detection and quantification of the producing cyanobacteria in different environments. Phylogenetic analyses of related clusters from a large number of strains has also allowed for the reconstruction of the evolutionary scenarios that have led to the emergence, diversification, and loss of such gene clusters in different strains and genera of cyanobacteria. Advances in the understanding of toxin biosynthesis and evolution have provided new methods for drinking-water quality control and may inspire the development of techniques for the management of bloom formation in the future.

Cyanobacterial toxins: biosynthetic routes and evolutionary roots

1. Intoduction 4348 2. Oxolane Macrodiolides 4348 2.1. Pamamycin 607 (1) 4348 2.1.1. Thomas Total Synthesis20 4349 2.1.2. Lee Total Synthesis28 4351 2.1.3. Metz Total Synthesis35 4353 2.1.4. Kang Total Synthesis41 4354 2.2. Amphidinolide X (2) 4356 2.2.1. Fürstner Total Synthesis59 4356 3. Oxane/Oxene Macrodiolides 4359 3.1. SCH 351448 (3) 4359 3.1.1. Lee Total Synthesis71 4359 3.2. Swinholide A (4) 4360 3.2.1. Paterson Total Synthesis82 4360 3.2.2. Nicolaou Total Synthesis83 4360 4. Cyclic Acetal Macrodiolides 4362 4.1. Cycloviracin B1 (5) 4362 4.1.1. Fürstner Total Synthesis96 4363 4.2. Glucolipsin A (6) 4366 4.2.1. Fürstner Total Synthesis117 4366 5. Cyclic Hemiketal Macrodiolides 4368 5.1. Boromycin (7) 4368 5.1.1. White Total Synthesis123 4368 5.2. Tartrolon B (8) 4369 5.2.1. Mulzer Total Synthesis130 4370 5.3. Debromoaplysiatoxin (9) and Aplysiatoxin (10) 4373 5.3.1. Kishi Total Synthesis142 4373 6. Conclusions 4375 7. Acknowledgments 4375 8. References 4375

/pdf/total-synthesis-of-oxacyclic-macrodiolide-natural-products-bq2vfw4hed.pdf

Jon S. Mynderse

Papers

Absolute stereochemistries of the aplysiatoxins and oscillatoxin A