title: Quercetin reduces serum homocysteine level in rats fed a methionine-enriched diet.
abstract: OBJECTIVE
  The aim of this study was to determine the effects of quercetin on homocysteine (Hcy) metabolism and hepatic antioxidant status in high methionine (Met)-fed rats.
  
  
  METHODS
  Rats were fed for 6 wk the following diets: control, 1.0% Met, 1.0% Met and 0.1% quercetin, 1.0% Met and 0.5% quercetin, 1.0% Met and 2.5% quercetin-supplemented diets. Serum Hcy, Met, cysteine, serine, taurine, glutathione (GSH), quercetin and its metabolites, and activities of alanine transaminase (ALT) and aspartate transaminase (AST) were assayed. Hepatic malondialdehyde, GSH and carbonyls, and activity of superoxide dismutase and ferric-reducing antioxidant power also were measured.
  
  
  RESULTS
  Serum Hcy was increased significantly after Met treatment and decreased after quercetin supplementation. Meanwhile, serum taurine was increased and serine decreased. However, the content of GSH in serum and liver was decreased in the quercetin-supplemented groups and activities of serum ALT and AST were enhanced in the 1.0% Met and 2.5% quercetin-supplemented groups.
  
  
  CONCLUSIONS
  Quercetin is effective in decreasing serum Hcy level in high Met-fed rats and one of possible mechanisms is associated with increased transsulfuration of Hcy. Quercetin can acts as a prooxidant at high intake levels.
authors: Institute of Health and Environmental Medicine, Tianjin, PR China.
authors: Bin
authors: B
authors: Meng
authors: Weina
authors: W
authors: Gao
authors: Jingyu
authors: J
authors: Wei
authors: Jijun
authors: J
authors: Yang
authors: Jianquan
authors: J
authors: Wu
authors: Lingling
authors: L
authors: Pu
authors: Changjiang
authors: C
authors: Guo
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000009:adverse effects / Q000378:metabolism / Q000627:therapeutic use*; D019587:Dietary Supplements / Q000009:adverse effects; D004195:Disease Models, Animal; D005978:Glutathione / Q000097:blood / Q000378:metabolism; D006710:Homocysteine / Q000097:blood; D020138:Hyperhomocysteinemia / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D015227:Lipid Peroxidation; D008099:Liver / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008715:Methionine; D009929:Organ Size; D018384:Oxidative Stress; D050050:Protein Carbonylation; D011794:Quercetin / Q000008:administration & dosage / Q000009:adverse effects / Q000378:metabolism / Q000627:therapeutic use*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D015430:Weight Gain
chemical_list: D000975:Antioxidants; D006710:Homocysteine; D008315:Malondialdehyde; D011794:Quercetin; D008715:Methionine; D005978:Glutathione