Author/Authors :
Farasat، Massoumeh نويسنده Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, IR Iran , , Khavarinejad، Ramazan-Ali نويسنده Department of Biology, Science and Research Branch, Islamic , , Nabavi، Seyed Mohammad Bagher نويسنده Deputy Head of Dept. of Marine Sciences, Department of Environment, IR Iran , , Namjooyan، Foroogh نويسنده Marine Pharmaceutical Research Center, Pharmacognosy Department, School of Pharmacy, Jundishapur University of Medical Sciences, Ahvaz, IR Iran ,
Abstract :
Background: Ulva genus, an edible seaweed, and an important food source in many south-east Asian countries is also recognized by its
synonymous name as Enteromorpha. Objectives: This study was carried out to evaluate antioxidant activity, contents of total phenolics, and flavonoids of methanolic extracts of
edible green seaweeds including Ulva clathrata (Roth) C. Agardh and three samples of Ulva prolifera O.F.Müller grown at different parts of
Bushehr Province along the northern coasts of the Persian Gulf. Materials and Methods: The seaweeds were collected from Bordekhoun, Northern Ouli, Taheri and Kangan coasts in December 2011.
Methanolic extracts of the seaweeds were assessed for their antioxidant activity using DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging
assay and was performed in a microplate reader. Total phenolics were determined by Folin-Ciocalteu reagent and flavonoid content was
evaluated by colorimetric method. Results: All samples showed antioxidant activity to various degrees. Ulva clathrata exhibited a high DPPH radical scavenging activity with a
low IC50 (the half-maximal inhibitory concentration) (0.715 ± 0.078 mg. mL-1). The highest phenolic content (4.468 ± 0.379 mg GAE g-1) (gallic acid
equivalent) and flavonoid content (45.577 ± 0.949 mg RE g-1) (rutin equivalent) were also observed in U .clathrata. The phenolic and flavonoid
contents showed positive correlations with the DPPH radical scavenging activity and negative correlations with IC50 (P < 0.01). Besides, Results
showed that there was a positive correlation between total phenolics and flavonoid content of extracts (P < 0.01). Conclusions: Strong positive and significant correlations between DPPH radical scavenging and phenolic and flavonoid contents showed
that, phenolic compounds, including flavonoids are the main contributors of antioxidant activity in these Ulva species and variations in
phenolics and flavonoid contents of the seaweed extracts may be due to the variation in physicochemical parameters such as salinity amongst
the selected stations.
