evaluation of in vitro antioxidant activities and antibacterial potentials of two brown algae extracts; lyengaria stellata and padina boergesenii inhabiting the persian gulf, iran

In-vitro antioxidant activities of semipurified methanolic extract of lyengaria stellata and padina boergesenii were evaluated using dpph radical-scavenging activity and reducing power. total phenolic contents (tpc) and total flavonoid contents (tfc) were also investigated. the acetone fraction of l. stellata contained the highest value (126.04±8.65 mg gae/g) of tpc, and the highest concentration of tfc (94±0.13 and 82±0.09 mg gae/g) was obtained in ethanol fractions of lyengaria stellata and padina boergesenii, respectively. the highest dpph scavenging activity (88.5%) was observed in the acetone fraction of l. stellata (1 mg/ml). the most significant reducing power was observed in the acetone fractions of both seaweeds at 100 mg/ml concentration (1.130±0.040 and 0.839±0.010, respectively). ethanol and acetone fractions of l. stellata showed the greatest antibacterial activity (29.6±0.5 and 28.0±0.7 mm, respectively) against staphylococcus aureus. the minimum value of mic was observed in acetone fractions of both seaweeds against s. aureus (50.7 and 50.8 μg/ml), while salmonella enterica showed the highest resistance to seaweeds extracts according to the– highest mic values (>200 mg/ml) and the smallest iz diameters. the extract of both algae showed considerable antioxidant activity according to dpph radical scavenging activity and reducing power assays.