Fatty Acids and Other Chemical Compositions of Some Seagrasses Collected from the Saudi Red Sea with Potential of Antioxidant and Anticancer Agents

The fatty acids (FAs), amino acids (AAs), phenolic and polysaccharides from Cymodocea serrulata , Halodule uninervis , Halophila stipulacea and Thalassia hemprichii were studied, their antioxidant and anticancer activities were also investigated. The results showed that T. hemprichii and C. serrulata were rich in gallic acid and protocatechuic acid with values of 45.26 and 25.26 mg/g, respectively. The polysaccharides of T. hemprichii and H. stipulacea were mainly composed of galactose (~ 21%), mannose (~ 14.5%) and glucose (~ 12.5%). The protein contents ranged from 3.06% ( H. stipulacea ) to 9.56% ( T. hemprichii ). Palmitic acid (C16:0) percentage was more than half of the total FAs content of H. uninervis and T. hemprichii , while linoleic acid (C18:2) was 35.7 and 28.6%, respectively, in both seagrasses. The highest steroid content was found in C. serrulata at 92.67%, and triterpenes lupeol (15.51%) and β-amyrin (16.59%) in H. stipulacea as the major oxygenated-unsaponifiable matters. T. hemprichii extract demonstrated the highest effective antioxidant activity with IC 50 value of 1.2 µg/ml, while H. uninervis extract displayed potential cytotoxic effect against human SKOV-3 ovarian and MCF-7 breast carcinoma cells with IC 50 values of 0.52 and 2.3 µg/ml, respectively.