title: Comparison and characterization of the antioxidant potential of 3 wild grapes--Vitis thunbergii, V. flexuosa, and V. kelungeusis.
abstract: This study considers a laboratory examination of the antioxidant performance of methanolic extracts from the leaves and stems of 3 common wild grapes (Vitis thunbergii, V. flexuosa, and V. kelungeusis) by various in vitro methods. It also seeks to identify the specific antioxidant constituent. Results revealed that, of these specimens, stem extracts of V. thunbergii exhibited good 1,1-diphenyl-2-picrylhydrazyl radical-scavenging and superoxide radical-scavenging performance and ferrous ion-chelating ability, as well as the highest total phenolic content (179.5 mg of GAE/g). The principal antioxidant, (+)-lyoniresinol-2a-O-β-D-glucopyranoside, was isolated from the stem extracts of V. thunbergii and identified. Removal of this compound from the extracts caused an approximate 2- to 5-fold decrease in antioxidant performance. This showed that (+)-lyoniresinol-2a-O-β-D-glucopyranoside is the primary antioxidant in wild grapes. Results also indicated that the antioxidant performance of (+)-lyoniresinol-2a-O-β-D-glucopyranoside was stronger than its lignan aglycone, (+)-lyoniresinol.
  
  
  CONCLUSIONS
  Of the 3 common wild grapes-Vitis thunbergii, V. flexuosa, and V. kelungeusis, the extracts or phytochemicals, derived from the V. thunbergii stems have excellent antioxidant properties, so they have great potential as a basis for natural health products that seek to prevent diseases caused by the overproduction of radicals.
authors.affiliation: Dept. of Forestry, Natl. Chung Hsing Univ., Taichung 402, Taiwan.
authors.forename: Yu-Tang
authors.initials: YT
authors.lastname: Tung
authors.forename: Kai-Chung
authors.initials: KC
authors.lastname: Cheng
authors.forename: Shang-Tse
authors.initials: ST
authors.lastname: Ho
authors.forename: Yong-Long
authors.initials: YL
authors.lastname: Chen
authors.forename: Tung-Lin
authors.initials: TL
authors.lastname: Wu
authors.forename: Ke-Chang
authors.initials: KC
authors.lastname: Hung
authors.forename: Jyh-Horng
authors.initials: JH
authors.lastname: Wu
mesh_terms: D000840:Anisoles / Q000032:analysis; D000975:Antioxidants / Q000032:analysis*; D001713:Biphenyl Compounds / Q000032:analysis; D005960:Glucosides / Q000032:analysis; D009281:Naphthalenes / Q000032:analysis; D010636:Phenols / Q000032:analysis; D010851:Picrates / Q000032:analysis; D010936:Plant Extracts / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D027843:Vitis / Q000737:chemistry*
chemical_list: D000840:Anisoles; D000975:Antioxidants; D001713:Biphenyl Compounds; D005960:Glucosides; D009281:Naphthalenes; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; C502379:lyoniresinol; C573572:lyoniresinol-2a-O-beta-D-glucopyranoside; C004931:1,1-diphenyl-2-picrylhydrazyl