Ln. Grinberg et al., PROTECTIVE EFFECTS OF TEA POLYPHENOLS AGAINST OXIDATIVE DAMAGE TO RED-BLOOD-CELLS, Biochemical pharmacology, 54(9), 1997, pp. 973-978
Tea polyphenols (TPP) from black and green teas were evaluated for the
ir antioxidant effects on normal red blood cells (RBC) and beta-thalas
semic RBC membranes challenged with exogenous oxidants in vitro. The T
PP of both types protected RBC against primaquine-induced lysis; they
also protected the whole cells and the membranes against H2O2-induced
lipid peroxidation so that about 80% protection was reached at [TPP] =
10 mu g/mL. TPP from black tea at the same concentration protected no
rmal RBC from morphological alterations caused by the peroxide treatme
nt. The mechanism of the effects of TPP was investigated using a chemi
cal system generating (OH)-O-. (iron + ascorbic acid). TPP from both b
lack and green teas inhibited the (OH)-O-. fluxes in a concentration-d
ependent manner, indicating the possibility of iron chelation by TPP.
Spectrophotometric titration revealed that TPP could stoichiometricall
y bind ferric iron to form a redox-inactive Fe-TPP complex. Quantitati
ve analysis suggests that one or more major catechins from the TPP pre
parations are the likely iron-binding compounds accounting for the ant
ioxidant effects of TPP on RBC. (C) 1997 Elsevier Science Inc.