Non-targeted metabolomics approach to assess the brown marine macroalga Dictyota dichotoma as a functional food using liquid chromatography with mass spectrometry

The study elucidates presence of 16 potential putative metabolites in Dictyota dichotoma through non-targeted secondary metabolite profile analysis using electrospray ionization negative mode of liquid chromatography with time-of-flight mass spectrometry. Two fatty acyl glycosides viz; 5-megastigmen-7-yne-3,9-diol 9-glucoside (biomarker for food consumption) and (3S,7E,9S)-9-hydroxy-4,7-megastigmadien-3-one 9-glucoside (nutrient, emulsifier, surfactant), an o-glycosyl compound 5-megastigmen-7-yne-3,9-diol 3-glucoside (biomarker for food consumption), all with m/z value 370.19 were detected. An acyclic monoterpenoid and diterpenoid viz; isodigeranyl and digeranyl (both with m/z 274.26; food biomarkers) were detected. Additionally, (3 ' x,5 ' a,9 ' x,10 ' b)-O-(3-hydroxy-6-oxo-7-drimen-11-yl) umbelliferone (m/z 396.19; nutrient, emulsifier, surfactant) and kamolonol (m/z 398.2; antibacterial, anti-tumor) were observed. Two angular pyranocoumarins: mammea C/AB cyclo D (m/z 398.2; food consumption biomarker) and 5-hydroxy-8, 8-dimethyl-6-(3-methyl-1-oxobutyl)-4-pentyl-2H,8H-benzo[1,2-b:3,4-b']dipyran-2-one (m/z 398.2; fruit constituent) were present. Two terpene lactones - galbanic acid (m/z 398.2; antimicrobial, anticoagulant, antiviral, anti-inflammatory, anti-cancer) and asacoumarin A (m/z 398.2; antiprotozoal, antiglycation activity) were detected. Armillaribin (m/z 398.2; food biomarker) along with glycinoeclepin B (m/z 558.28; nutrient, emulsifier, surfactant) was noted. Two flavonoids; (S)-(E)-2 '-(3,6-dimethyl-2-heptenyl)-3 ',4 ',7-trihydroxyflavanone and (S)-(E)-8-(3,6-dimethyl-2-heptenyl)-4 ',5,7-trihydroxyflavanone (m/z 396.19) and a drug triclofos (m/z 227.89; sedative) were detected. This study highlights the metabolic makeup of D. dichotoma collected from Kachchh coast thereby, accentuating the probability of its inclusion as a promising ingredient in functional foods from algal origin.