Chemistry and biology of novel cyanobacterial secondary metabolites from Guam

Marine cyanobacteria represent one of the most prolific sources of bioactive secondary metabolites with promising biomedical potential. Among the marine cyanobacteria, Lyngbya spp. are well known for their enormous potential to mix nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) pathways for the production of peptide-polyketide hybrids with a wide range of biological activities. In our continuous quest for novel drug leads from marine cyanobacteria, Guamanian varieties of the marine cyanobacteria Lyngbya spp. from Piti Bay were explored. This work led to the identification of a group of bioactive compounds which contain structural moieties with characteristic biosynthetic signatures of this organism. We will present the structure elucidation and bioactivity assessment of some of those compounds. Structural characterization was done using several techniques including nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS) and chemical modifications followed by enantioselective LC/MS. Biological characterization involved cytotoxicity screening in cancer cell lines, antibacterial assays and cannabimimetic activity evaluation.