ISSN:
1420-9071
Schlagwort(e):
Antioxidant
;
epigallocatechin gallate
;
tea polyphenols
;
3-nitrotyrosine
;
8-oxodeoxyguanosine
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
,
Medizin
Notizen:
Abstract Reaction with peroxynitrite at pH 7.4 and 37°C was found to increase the 8-oxodeoxyguanosine levels in calf thymus DNA 35-38-fold. This oxidation of deoxyguanosine, as well as the peroxynitrite-mediated nitration of tyrosine to 3-nitrotyrosine, was significantly inhibited by ascorbic acid, glutathione and (−)-epigallocatechin gallate, a polyphenolic antioxidant present in tea. For 50% inhibition of the oxidation of deoxyguanosine to 8-oxodeoxyguanosine, 1.1, 7.6 of 0.25 mM ascorbate, glutathione or (−)-epigallocatechin gallate, respectively, was required. For 50% inhibition of tyrosine nitration, the respective concentrations were 1.4, 4.6 or 0.11 mM. Thus, (−)-epigallocatechin gallate is a significantly better inhibitor of both reactions than either ascorbate or glutathione. Reaction of (−)-epigallocatechin gallate with peroxynitrite alone resulted in the formation of a number of products. Ultraviolet spectra of two of these suggest that the tea polyphenol and/or its oxidation products are nitrated by peroxynitrite.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF01938881
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