. The Phaeophyceae members were observed with higher content of (with the range 20.72-32.89mg/g and mean of 26.80) flavonoids than the Chlorophyceae and Rhodophyceae. Among the fifteen species analyzed, Enteromorpha compressa(33.39mg/g) and Padina tetrastromatica(32.89mg/g) have higher content.