Descrição
Cyanobacteria are widely recognized as a valuable source of bioactive metabolites. The majority of such compounds have
been isolated from so-called complex cyanobacteria, such as filamentous or colonial forms, which usually display a larger
number of biosynthetic gene clusters in their genomes, when compared to free-living unicellular forms. Nevertheless,
picocyanobacteria are also known to have potential to produce bioactive natural products. Here, we report the isolation of
hierridin B from the marine picocyanobacterium Cyanobium sp. LEGE 06113. This compound had previously been isolated
from the filamentous epiphytic cyanobacterium Phormidium ectocarpi SAG 60.90, and had been shown to possess
antiplasmodial activity. A phylogenetic analysis of the 16S rRNA gene from both strains confirmed that these cyanobacteria
derive from different evolutionary lineages. We further investigated the biological activity of hierridin B, and tested its
cytotoxicity towards a panel of human cancer cell lines; it showed selective cytotoxicity towards HT-29 colon
adenocarcinoma cells.
; Costa, Margarida 
