Rooibos Tea (Aspalathus
linearis) Partially Prevents Oxidative Stress in
Streptozotocin-Induced Diabetic Rats
O. ULIČNÁ1, O. VANČOVÁ1, P.
BOŽEK2, J. ČÁRSKY3, K. ŠEBEKOVÁ4,
P. BOOR4,
M. NAKANO5, M. GREKSÁK6
1Laboratory of Pharmacobiochemistry, Third Department
of Internal Medicine, Faculty of Medicine, Comenius University,
2Department of Biochemistry and Hematology, State
Hospital, 3Institute of Medical Chemistry,
Biochemistry and Clinical Biochemistry, Faculty of Medicine,
Comenius University, 4Slovak Medical University,
Department of Clinical and Experimental Pharmacology,
Bratislava, Slovak Republic, 5Nagoya Keizai
University, Inuyama, Japan and 6Institute of Animal
Biochemistry and Genetics, Slovak Academy of Sciences, Ivanka
pri Dunaji, Slovak Republic
Received March 3, 2005
Accepted May 12, 2005
On-line available May 24, 2005
Summary
The aim of this study was to investigate the effects of rooibos
tea as a natural source of a wide scale of antioxidants on the
prevention and treatment of oxidative stress in
streptozotocin-induced diabetic rats. Expected significant
changes of biochemical parameters characteristic for
experimental diabetic state were found in plasma and tissues
eight weeks after single dose streptozotocin application.
Administration of aqueous and alkaline extracts of rooibos tea
(or N-acetyl-L-cysteine for comparison) to diabetic rats did not
affect markers of the diabetic status (glucose, glycated
hemoglobin and fructosamine). Besides the parameters
characterizing hepatotoxic effect of streptozotocin, rooibos tea
significantly lowered advanced glycation end-products (AGEs) and
malondialdehyde (MDA) in the plasma and in different tissues of
diabetic rats, particularly MDA concentration in the lens. From
these results we can conclude that antioxidant compounds in
rooibos tea partially prevent oxidative stress and they are
effective in both hydrophobic and hydrophilic biological
systems. Therefore, rooibos tea as a commonly used beverage can
be recommended as an excellent adjuvant support for the
prevention and therapy of diabetic vascular complications,
particularly for protecting ocular membrane systems against
their peroxidation by reactive oxygen species.
Key words
Rooibos tea • Aspalathus linearis • Oxidative stress •
Streptozotocin-induced diabetes
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