title: The effect of green tea in oxidative stress.
abstract: OBJECTIVE
  Green tea, an infusion prepared with the leaves of Camellia sinensis is particularly rich in flavonoids, which are strong antioxidants. Tea drinking, by providing antioxidants, may become valuable in several oxidative stress conditions. Our aim was to evaluate the effect of green tea drinking on some factors reflecting the development of oxidative stress in plasma and in erythrocytes.
  
  
  METHODS
  The study was performed in 34 Portuguese subjects. We evaluated the total antioxidant status (TAS), the lipid peroxidation products-malonyldialdehyde (MDA) and malonyldialdehyde+4-hydroxy-2(E)-nonenal (MDA+4-HNE)-and the oxidative changes in erythrocyte membrane, namely membrane bound haemoglobin (MBH) and the band 3 profile. Analytical evaluations were performed after 3 weeks drinking 1l of water daily, and after 4 weeks drinking 1l of green tea daily. Tea was prepared daily at the same conditions of temperature, time of infusion and concentration.
  
  
  RESULTS
  After green tea drinking, we found a significant reduction in serum levels of MDA and MDA+4-HNE and in the oxidative stress within the erythrocyte, as suggested by a significantly lower value of MBH and by changes in band 3 profile towards a normal mean profile, namely an increase in the band 3 monomer. A rise in the antioxidant capacity was also observed.
  
  
  CONCLUSIONS
  Our data suggest for green tea drinking a beneficial effect, by reducing the development or the enhancement of oxidative stress and, therefore, protecting the individual for oxidative stress diseases. Moreover, we propose further studies about the value of band 3 profile and of MBH in providing a cumulative measurement of the effect of green tea drinking upon the oxidative stress in cells. Moreover, further studies are also needed, to clarify the effect of green tea consumption, the value of regular green tea consumption and the way it should be prepared to reach a healthy effect.
authors.affiliation: Faculdade Farmácia, Serviço Bioquímica, Universidade Porto, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Coimbra
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Castro
authors.forename: Petronila
authors.initials: P
authors.lastname: Rocha-Pereira
authors.forename: Irene
authors.initials: I
authors.lastname: Rebelo
authors.forename: Susana
authors.initials: S
authors.lastname: Rocha
authors.forename: Alice
authors.initials: A
authors.lastname: Santos-Silva
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000494:pharmacology*; D001628:Beverages; D028241:Camellia sinensis / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects*; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D013662:Tea
chemical_list: D000975:Antioxidants; D013662:Tea; D008315:Malondialdehyde