title: In vitro and in vivo antioxidant and antimutagenic activities of polyphenols extracted from hops (Humulus lupulus L.).
abstract: BACKGROUND
  Hops (Humulus lupulus L.) contain 40-140 mg g(-1) polyphenols. The objective of this study was to determine the phenolic composition of a high-purity (total phenolic content = 887 mg g(-1) ) hop polyphenol extract (HPE) and evaluate its antioxidant activities in vivo and in vitro and its antimutagenic activity. The antioxidant activity of HPE was compared with the activity of green tea polyphenols.
  
  
  RESULTS
  The phenolic compositions of HPE were more than 55% proanthocyanidins and more than 28% flavonoid glycosides. In vitro, HPE effectively scavenged α,α-diphenyl-β-picrylhydrazyl, hydroxyl and superoxide anion radicals, and inhibited DNA oxidative damage. In vivo, oral HPE at a polyphenol dose of 200-800 mg kg(-1) body weight significantly prevented a bromobenzene-induced decrease in liver superoxide dismutase and glutathione peroxidase activity, and decreased levels of liver thiobarbituric acid reactive substances in bromobenzene-treated mice. An oral dose of 20-80 mg kg(-1) body weight HPE significantly reduced the frequency of bone marrow micronuclei induced by cyclophosphamide. The antioxidant activities of hop polyphenols in vitro and in vivo were higher than green tea polyphenols at the same concentration.
  
  
  CONCLUSIONS
  Hop polyphenols had the same or higher antioxidant activity than tea polyphenols. Hop polyphenols might be useful as natural antioxidants and antimutagens.
authors: College of Life Science, Shanxi University, Taiyuan, 030006, China.
authors: Xuping
authors: X
authors: Wang
authors: Lei
authors: L
authors: Yang
authors: Xiaolan
authors: X
authors: Yang
authors: Yanhua
authors: Y
authors: Tian
mesh_terms: D000818:Animals; D016587:Antimutagenic Agents / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D001969:Bromobenzenes / Q000494:pharmacology; D028241:Camellia sinensis / Q000737:chemistry; D004249:DNA Damage / Q000187:drug effects; D005260:Female; D005419:Flavonoids / Q000032:analysis; D005979:Glutathione Peroxidase / Q000032:analysis; D027582:Humulus / Q000737:chemistry*; D066298:In Vitro Techniques; D008099:Liver / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology; D008297:Male; D051379:Mice; D015162:Micronucleus Tests; D010084:Oxidation-Reduction; D010936:Plant Extracts / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D059808:Polyphenols / Q000302:isolation & purification / Q000494:pharmacology*; D044945:Proanthocyanidins / Q000032:analysis; D013482:Superoxide Dismutase / Q000032:analysis; D013662:Tea / Q000737:chemistry; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis
chemical_list: D016587:Antimutagenic Agents; D000975:Antioxidants; D001969:Bromobenzenes; D005419:Flavonoids; D010936:Plant Extracts; D059808:Polyphenols; D044945:Proanthocyanidins; D013662:Tea; D017392:Thiobarbituric Acid Reactive Substances; C032036:bromobenzene; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase
keywords: Humulus lupulus L; antimutagenic activity; antioxidant activity; hops; phenolic composition; proanthocyanidins