Biological potential of marine macroalgae of the genus Cystoseira.

In the present investigation the acetone extracts of three macroalgae, Cystoseira amentacea, Cystoseira barbata and Cystoseira compressa, were tested for antioxidant, antimicrobial and cytotoxic potential. As a result of the study, C. amentacea extract had more potent free radical scavenging activity (IC50 = 409.81 μg/mL) than C. barbata and C. compressa extracts. For reducing power, measured values of absorbance varied from 0.0352 to 0.8873. The IC50 values for superoxide anion scavenging activity for different extracts were 521.45-976.62 μg/mL. Total phenol and flavonoid contents in extracts were 39.96-81.28 μg PE/mg and 20.85-64.58 μg RE/mg respectively. Further, all three Cystoseira species exhibited a similar antimicrobial activity. The lowest MIC value (0.312 mg/mL) was shown in the extract obtained from C. compressa against Bacillus subtilis. Finally, extract of C. amentacea expressed the strongest cytotoxic activity toward tested cell lines with IC50 values ranging from 94.72 to 186.55 μg/mL. Based on these results, it can be stated that the tested macroalgae can be used as potential natural antioxidants and antimicrobial and cytotoxic agents.