title: Antioxidant Properties of two Edible Green Seaweeds From Northern Coasts of the Persian Gulf.
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.
  
  
  OBJECTIVE
  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.
  
  
  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.
authors.affiliation: Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, IR Iran.
authors.forename: Massoumeh
authors.initials: M
authors.lastname: Farasat
authors.affiliation: Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, IR Iran.
authors.forename: Ramazan-Ali
authors.initials: RA
authors.lastname: Khavari-Nejad
authors.affiliation: Faculty of Marine Science, University of Marine Sciences and Technology, Khorramshahr, IR Iran.
authors.forename: Seyed Mohammad Bagher
authors.initials: SM
authors.lastname: Nabavi
authors.affiliation: Marine Pharmaceutical Research Center, Pharmacognosy Department, School of Pharmacy, Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Foroogh
authors.initials: F
authors.lastname: Namjooyan
keywords: Antioxidant Capacity; DPPH; Flavonoid; Total Phenolics