Evaluation of in vitro Antioxidant Activities and Antibacterial Potentials of Two Brown Algae Extracts; Lyengaria stellata and Padina boergesenii Inhabiting the Persian Gulf, Iran

Abstract In-vitro antioxidant activities of semi-purified 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 (۱۲۶.۰۴±۸.۶۵ mg GAE/g) of TPC, and the highest concentration of TFC (۹۴±۰.۱۳ and ۸۲±۰.۰۹ mg GAE /g) was obtained in ethanol fractions of Lyengaria stellata and Padina boergesenii, respectively. The highest DPPH scavenging activity (۸۸.۵%) was observed in the acetone fraction of L. stellata (۱ mg/ml). The most significant reducing power was observed in the acetone fractions of both seaweeds at ۱۰۰ mg/ml concentration (۱.۱۳۰±۰.۰۴۰ and ۰.۸۳۹±۰.۰۱۰, respectively). Ethanol and acetone fractions of L. stellata showed the greatest antibacterial activity (۲۹.۶±۰.۵ and ۲۸.۰±۰.۷ mm, respectively) against Staphylococcus aureus. The minimum value of MIC was observed in acetone fractions of both seaweeds against S. aureus (۵۰.۷ and ۵۰.۸ µg/ml), while Salmonella enterica showed the highest resistance to seaweeds extracts according to the– highest MIC values (>۲۰۰ 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.

Keywords:

Antibacterial Activity , Antioxidant potential , Persian Gulf , Seaweeds , Lyengaria stellate , Padina boergesenii