Brown Algae from San Andres Island, Southwest Caribbean: A Nuclear Magnetic Resonance Spectroscopy–Metabolomic Study

<b>Background:</b> Brown algae from the order Dictyotales are known to produce specialized metabolites with a wide array of biological activities. Studying these compounds is important for understanding their ecological roles, exploring biomedical potential and developing biotechnological applications. <b>Methods:</b> To evaluate the metabolic diversity of brown algae from the shallow habitats of the northern region of San Andrés Island (Colombia, SW Caribbean), a metabolic profiling approach was employed, based on ¹H-NMR spectra taken from organic extracts. Four sampling expeditions were conducted to collect the most abundant species, taking into account the taxonomic identity, growth substrate and collection date. <b>Results:</b> Five species were found and identified as <i>Canistrocarpus crispatus</i>, <i>Stypopodium zonale</i>, <i>Dictyopteris delicatula</i>, <i>Padina gymnospora</i> and <i>Dictyota</i> spp. Multivariate analyses applied to these spectra revealed that <i>S. zonale</i> and <i>C. crispatus</i> differentiated from the other samples mainly due to the signals for meroditerpenes and diterpenes, respectively. <i>S. zonale</i> had differential metabolic production observed when comparing algae collected in rocky bottoms with thalli growing on dead coral. This difference was attributed to changes in concentrations of the meroditerpene atomaric acid (<b>1</b>). Meanwhile, the major metabolite found in <i>C. crispatus</i> samples was dictyol B acetate (<b>2</b>). <b>Conclusions:</b> NMR metabolomics of San Andrés brown algae differentiated species based on lipid content and metabolic complexity. Notably, prenylated-guaiane diterpenes characterized <i>C. crispatus</i>, and meroditerpenoid concentrations varied in <i>S. zonale</i>. Temporal lipid variations were observed in <i>P. gymnospora</i>, while juvenile <i>Dictyota</i> spp. presented a less complex metabolic signature.