title: Antioxidant activity of herbaceous plant extracts protect against hydrogen peroxide-induced DNA damage in human lymphocytes.
abstract: BACKGROUND
  Herbaceous plants containing antioxidants can protect against DNA damage. The purpose of this study was to evaluate the antioxidant substances, antioxidant activity, and protection of DNA from oxidative damage in human lymphocytes induced by hydrogen peroxide (H2O2). Our methods used acidic methanol and water extractions from six herbaceous plants, including Bidens alba (BA), Lycium chinense (LC), Mentha arvensis (MA), Plantago asiatica (PA), Houttuynia cordata (HC), and Centella asiatica (CA).
  
  
  METHODS
  Antioxidant compounds such as flavonol and polyphenol were analyzed. Antioxidant activity was determined by the inhibition percentage of conjugated diene formation in a linoleic acid emulsion system and by trolox-equivalent antioxidant capacity (TEAC) assay. Their antioxidative capacities for protecting human lymphocyte DNA from H2O2-induced strand breaks was evaluated by comet assay.
  
  
  RESULTS
  The studied plants were found to be rich in flavonols, especially myricetin in BA, morin in MA, quercetin in HC, and kaemperol in CA. In addition, polyphenol abounded in BA and CA. The best conjugated diene formation inhibition percentage was found in the acidic methanolic extract of PA. Regarding TEAC, the best antioxidant activity was generated from the acidic methanolic extract of HC. Water and acidic methanolic extracts of MA and HC both had better inhibition percentages of tail DNA% and tail moment as compared to the rest of the tested extracts, and significantly suppressed oxidative damage to lymphocyte DNA.
  
  
  CONCLUSIONS
  Quercetin and morin are important for preventing peroxidation and oxidative damage to DNA, and the leaves of MA and HC extracts may have excellent potential as functional ingredients representing potential sources of natural antioxidants.
authors.affiliation: Department of Nutrition and Health Sciences, Chinese Culture University, Taipei 11114, Taiwan. pychao@faculty.pccu.edu.tw.
authors.forename: Kuan-Hung
authors.initials: KH
authors.lastname: Lin
authors.forename: Yan-Yin
authors.initials: YY
authors.lastname: Yang
authors.forename: Chi-Ming
authors.initials: CM
authors.lastname: Yang
authors.forename: Meng-Yuan
authors.initials: MY
authors.lastname: Huang
authors.forename: Hsiao-Feng
authors.initials: HF
authors.lastname: Lo
authors.forename: Kuang-Chuan
authors.initials: KC
authors.lastname: Liu
authors.forename: Hwei-Shen
authors.initials: HS
authors.lastname: Lin
authors.forename: Pi-Yu
authors.initials: PY
authors.lastname: Chao
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000302:isolation & purification / Q000494:pharmacology*; D001681:Biological Assay; D002478:Cells, Cultured; D002839:Chromans / Q000737:chemistry; D020552:Comet Assay; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D005260:Female; D044948:Flavonols / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D019787:Linoleic Acid / Q000737:chemistry; D015227:Lipid Peroxidation / Q000187:drug effects; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D000432:Methanol; D008875:Middle Aged; D009691:Nucleic Acid Denaturation / Q000187:drug effects; D018384:Oxidative Stress; D010946:Plants, Medicinal / Q000737:chemistry*; D059808:Polyphenols / Q000302:isolation & purification / Q000494:pharmacology*; D012997:Solvents; D014867:Water
chemical_list: D000975:Antioxidants; D002839:Chromans; D004365:Drugs, Chinese Herbal; D044948:Flavonols; D059808:Polyphenols; D012997:Solvents; D014867:Water; D019787:Linoleic Acid; D006861:Hydrogen Peroxide; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; D000432:Methanol