title: Theoretical elucidation of activity differences of five phenolic antioxidants.
abstract: OBJECTIVE
  To verify the effectiveness of structure-activity relationship (SAR) and theoretical calculation methods for antioxidants.
  
  
  METHODS
  Preliminary elucidation on the differences of activities of 5 antioxidants was performed by SAR. Then semiempirical quantum chemistry method AM1 was employed to calculate the delta HOF value, the difference between the heat of formation of antioxidant and its free radical, which was used as a theoretical parameter to elucidate the differences of activities of the antioxidants thoroughly.
  
  
  RESULTS
  delta HOF values of antioxidants were obtained as follows: ferulic acid, 150.58 kJ.mol-1; anion of ferulic acid, 122.64 kJ.mol-1; modified ferulic acid, 137.70 kJ.mol-1; anion of modified ferulic acid, 118.99 kJ.mol-1; salvianic acid, 134.17 kJ.mol-1; rutin, 137.83 kJ.mol-1, L-EGCG, 124.39 kJ.mol-1; paeonol, 176.79 kJ.mol-1. The differences of the antioxidant activities were elucidated, and how to further enhance the antioxidant activity was investigated as well.
  
  
  CONCLUSIONS
  The SAR and calculation methods are rather effective to elucidate the differences of antioxidant activities, and present some new clues for structural modification of antioxidants to increase their activities.
authors.affiliation: Department of Biology, Shandong Teachers' University, Ji-nan, China. zhysdtu@jn-public.sd.cninfo.net
authors.forename: H Y
authors.initials: HY
authors.lastname: Zhang
authors.forename: N
authors.initials: N
authors.lastname: Ge
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Zhang
mesh_terms: D000098:Acetophenones / Q000737:chemistry / Q000494:pharmacology; D000975:Antioxidants / Q000737:chemistry* / Q000494:pharmacology; D002392:Catechin / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D003373:Coumaric Acids / Q000737:chemistry / Q000494:pharmacology; D005609:Free Radicals; D015394:Molecular Structure; D012431:Rutin / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: D000098:Acetophenones; D000975:Antioxidants; D003373:Coumaric Acids; D005609:Free Radicals; C013638:paeonol; D012431:Rutin; D002392:Catechin; C004999:ferulic acid; C045651:epigallocatechin gallate