title: Free radical scavenging actions of three Trifolium species in the protection of blood plasma antioxidant capacity in vitro.
abstract: BACKGROUND
  Three clover [Trifolium L. (Leguminosae)] species were selected on the basis of data from traditional medicine, phytochemical profiles, and agricultural significance.
  
  
  OBJECTIVE
  The in vitro evaluations of free radical scavenging properties, ferric reducing abilities, and antioxidant effects of extracts from T. pratense L. (crude extract and phenolic fraction), T. pallidum L., and T. scabrum L. (phenolic fractions) were performed.
  
  
  METHODS
  Activities of the Trifolium extracts were determined at their final concentrations of 1.5-50 µg/ml. Free radical scavenging properties of methanol extract solutions were estimated by the reduction of DPPH(•) and ABTS(•) radicals. Measurements of the total antioxidant capacity (TAC) were carried out to assess the antioxidant activities of the extracts in human blood plasma under conditions of oxidative stress, induced by 200 μM peroxynitrite.
  
  
  RESULTS
  The phenolic fraction of T. pratense displayed the strongest ABTS(•) and DPPH(•) radical scavenging effects (EC50 value of 21.69 and 12.27 µg/ml, respectively). The EC50 value for T. pallidum extract attained 29.77 and 30.06 µg/ml. The two remaining extracts were less potent scavengers (EC50 value higher than 50 µg/ml). Similar differences were obtained during evaluation of the ferric reducing abilities. Analysis of antioxidant properties of the extracts in blood plasma did not provide such evident differences in their actions, however, it indicated that the T. pratense phenolic fraction displayed the strongest effect.
  
  
  CONCLUSIONS
  The examined Trifolium extracts partly protected blood plasma and enhanced its non-enzymatic antioxidant defense against harmful action of peroxynitrite in vitro.
authors: Department of General Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz , Lodz , Poland and.
authors: Joanna
authors: J
authors: Kolodziejczyk-Czepas
authors: Pawel
authors: P
authors: Nowak
authors: Barbara
authors: B
authors: Moniuszko-Szajwaj
authors: Iwona
authors: I
authors: Kowalska
authors: Anna
authors: A
authors: Stochmal
mesh_terms: D052160:Benzothiazoles / Q000737:chemistry; D001713:Biphenyl Compounds / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D016166:Free Radical Scavengers / Q000097:blood / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D000432:Methanol / Q000737:chemistry; D018384:Oxidative Stress / Q000187:drug effects*; D008517:Phytotherapy; D010851:Picrates / Q000737:chemistry; D035261:Plant Components, Aerial; D010936:Plant Extracts / Q000097:blood / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D012997:Solvents / Q000737:chemistry; D013451:Sulfonic Acids / Q000737:chemistry; D029921:Trifolium / Q000737:chemistry
chemical_list: D052160:Benzothiazoles; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D010851:Picrates; D010936:Plant Extracts; D012997:Solvents; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C004931:1,1-diphenyl-2-picrylhydrazyl; D000432:Methanol
keywords: Clover; oxidative stress; peroxynitrite