Variation in bioactive compounds in some seaweeds from Abo Qir bay, Alexandria, Egypt

This study aims to assess the bioactive compounds and antioxidant activities of three selected seaweeds [Cladophora pellucida (Chlorophyta), Padina tetrastromatica (Phaeophyta) and Laurencia papillosa (Rhodophyta)] collected from Abo Qir bay, Alexandria, Egypt. L. papillosa demonstrated the greatest DPPH radical scavenging activity (52.1 +/- A 1.23 %) and beta carotene content (3675.6 +/- A 134.6 IU/100 g) in comparison with the other seaweed species. The highest contents of phenol (0.26 +/- A 0.005 mg/g DW) and flavonoid (5.6 +/- A 0.8 mg CE/100 g DW) were observed in P. tetrastromatica and C. pellucida, respectively. P. tetrastromatica showed the highest ascorbic acid content (26.0 +/- A 0.98 mg%). Nineteen fatty acid methyl esters were detected in the tested seaweeds by gas chromatography, while C. pellucida had the highest total concentrations of fatty acids and the highest omega 3 and omega 6 fatty acids. Polysaccharides (cladophoran, fucoidan and agar) were identified in C. pellucida, P. tetrastromatica and L. papillosa, respectively, by Fourier transform infrared with attenuated total reflectance. These findings recommend the studied seaweeds to be used as a novel source of natural bioactive compounds and antioxidant agents for food supplements, cosmetics and pharmaceutical industries.