Characterization and metabolomics profiling of Kappaphycus alvarezii seaweed extract

Kappaphycus alvarezii (Red seaweed) extract (KAE) has an important bio-stimulatory role for enhancing crop productivity and improving animal nutrition and health. However, little knowledge exists on the gamut of compounds present in it and their specific bioactivities. In this study, KAE was screened for the presence of metabolites and was characterized for its association with known bioactivities. The results revealed that phytochemical compounds such as phenols (TPC = 1108.67 ± 98.51 mg GA 100 g⁻¹), flavonoids (TFC = 15.26 ± 0.95 mg QE 100 g⁻¹), steroids, quinones were also present apart from the primary metabolites like carbohydrates (5.70 ± 0.13 g 100 g⁻¹), proteins (3.4 ± 0.94 g 100 g⁻¹), lipids (2.13 ± 0.06 g 100 g⁻¹), Carotenoids (0.64 ± 0.05 mg g⁻¹), Ascorbic acid (2.09 ± 0.3 mg g⁻¹) and antioxidant activity (DPPH = 345.96 ± 30.56 μg TE g⁻¹) in the Kappaphycus alvarezii extract powder. Among the 69 compounds observed in the methanolic extract of KAE (through Q-TOF-HRMS), 34 compounds were annotated and further analyzed using mass fragmentation studies (MS/MS). In this context, kinetin, sulfabenzamide, 1-phosphatidyl-1D-myoinositol, dodecanamide and several others were found to be prominent compounds having known bioactivities such as role in plant growth promotion, hormonal signaling, photo-protection, imparting disease resistance, antioxidant, anti-microbial, and anti-herbivory properties. Many compounds annotated are also pharmaceutically important, thus indicating the vast scope seaweeds might have in varied industries. In most of the studies, primary compounds such as plant growth hormones, minerals, proteins, polysaccharides and quaternary ammonium compounds were only reported from the KAE, however the present study reports a range of other metabolites having significant biological activities.