Nutritional values, antioxidant, and cytotoxic activities of selected edible marine macroalgae: a comparative study

Abstract The objective of this study is to assess the chemical composition, nutritional values, and bioactivities of four macroalgae from the Egyptian Red Sea coasts using standard methods. Of these, three Rhodophyceae species, Digenea simplex ( D. simplex ), Laurencia papillosa ( L. papillosa ), and Galaxaura oblongata ( G. oblongata ), and one Phyaeophyceae species, Turbinaria decurrens ( T. decurrens ), were selected. The results of proximate and chemical composition analyses based on the algal dry weight (DW) showed that carbohydrate content was the highest, ranging from 32.47 ± 1.03% to 45.5 ± 1.23%. Other algal constituents, including ash, protein, moisture, sulfate, lipid, phenolics, and flavonoids, have contents that depend on the algal species. Besides, HPLC analysis revealed that each algal extract contained varying amounts of nine phenolic acids. Atomic absorption spectrometry, the HPLC-Pico-Tag method, the ion chromatography technique, and GC/MS analyses were used to determine the chemical profiles of the elemental, amino acid, halide, and fatty acid of each algal extract. Bioactivities revealed that both the • DPPH and ABTS assays showed that all the algae studied had a significant ability to scavenge free radicals in a dosage-dependent way. They also had strong selective cytotoxic activity against HEPG-2 and HCT-116 cell lines, but only weak activity against MCF-7 and A549 cell lines. Finally, our findings suggested that the selected algae might be efficiently used as nutraceuticals and functional foods, indicating an increase in their proliferation.