Bioactive Compound Profiling of Agarophyte Seaweed (Gelidiella acerosa, Gracilaria arcuata, and Gracilaria verrucosa) Based on LC-HRMS Metabolomic and Molecular Networking Approach

Abstract

To date, exploration of Gracilaria and Gelidiella's bioactive compounds has been conducted using conventional methods that require a long time, high costs, and significant effort. Currently, metabolomic profiling and molecular networking have emerged as methods of exploring bioactive compounds. This study aimed to perform bioactive compound profiling through a metabolomic LC-HRMS-based and molecular networking approach in Gelidiella acerosa, Gracilaria arcuata, and Gracilaria verrucosa. All chromatograms and MS/MS spectra obtained for three crude extracts were digitally converted into an mzXML file using MSConvert, submitted to the Global Natural Product Social (GNPS), and visualized in Cytoscape 3.9.1. In total, nine dereplicated compounds were identified: 11-Deoxyprostaglandin (m/z 324.214), Diacylglyceryl trimethylhomoserines (DGTS) (m/z 684.575), Glycochenodeoxy acid (m/z 448.369), Lysophosphatidylcholine (m/z 522.350), Diacylglyceryl trimethylhomoserines (DGTS) (m/z 656.557), Pheophorbide A (m/z 593.266), Pyropheophorbide A (m/z 593.266), (2R,3R)-2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-2,3-dihydro-4H-chromen-4-one (m/z 303.15), and Polyporic acid (m/z 293.156). These compounds are typically classified as fatty acids, lipids, terpenoids, alkaloids, shikimates, and phenylpropanoids. The molecular networking and metabolite clustering showed an interesting pattern where some compounds were produced only by one species, some by two species, and some by all three. These compounds may have pharmaceutical potential based on their chemical properties and reported activities.