Secondary Metabolites from Cyanobacteria: Complex Structures and Powerful Bioactivities

Abstract

This review presents natural products from cyanobacteria. Several classes of secondary metabolites are highlighted. Toxic metabolites from these prokaryotic photosynthetic organisms include compounds such as microcystin, anatoxin and saxitoxin, which display hepatotoxicity and neurotoxicity. Their potential as drugs in cancer therapy is discussed based on the cryptophycin class of potent cytotoxic agents. The next part of this review highlights iron chelators from cyanobacteria, including schizokinen, synechobactin and anachelin. The biogenesis of anachelin is investigated as its mechanism of iron acquisition. Several indole alkaloids are then reviewed, from simple carbolines such as bauerines and nostocarboline to complex polycyclic structures such as hapalindole, welwitindolinone and ambiguine. The latter compounds present fascinating structure combined with powerful bioactivities and interesting biogenetic pathways. In the last part, protease inhibitors from cyanobacteria are discussed (cyanopeptolins, micropeptin and oscillapeptin) and their structure/activity relationships and selectivity for trypsin / chymotrypsin are presented. All these examples highlight the large structural variety of cyanobacterial metabolites combined with powerful biological activities. Cyanobacteria can thus be considered a prime source both for novel bioactive compounds and for leads for drugs.

Isolation and Molecular Identification of Some Blue-Green Algae (Cyanobacteria) from Freshwater Sites in Tokat Province of Turkey

“…They have gram negative cell walls and their peptidoglycan layers are ranging in 10-200 nm of thickness (Gademan and Portman, 2008). Dominant pigments present in cyanobacteria are chlorophyll a, chlorophyll c and phycocyanine which contributing to their distinct bluegreen colorization.…”

Controlling Protein Transport by Small Molecules

“…[27] This remarkable selectivity has been attributed to interference with pRB tumor suppressors, as reported in the original isolation publication. [27] In the context of our program on the synthesis of biologically active natural products, [29][30][31][32][33][34][35][36] and intrigued by this remarkable selectivity, we have embarked on a total synthesis of these polyketides for further biological evaluation. [24,37] In particular, we wanted to examine whether these compounds also constitute inhibitors of the CRM1 mediated nuclear export.…”

Cyanobacteria: an emerging source for drug discovery

“…During recent decades, cyanobacteriologists have started to pay attention to the bioactivity of cyanobacteria. 10,11 A literature study of Journal of Natural Products (January 2007-October 2008), revealed the discovery of 38 new compounds from cyanobacteria among which 8 are antiprotozoal, 7 are antibacterial, 2 are antiviral, 6 are cytotoxic, 7 are protease inhibitors, 1 is a Ca 2+ channel inhibitor and the remainder (7) show no bioactivity (Figure 1). The high degree of diversity in the bioactivities of cyanobacteria is due to the broad spectrum of its secondary metabolites.…”