Protective effects of black tea extract against oxidative DNA damage in human lymphocytes

Abstract

The aim of the present study was to examine the genoprotective and radioprotective effects of black tea extract (BTE) against the induction of single strand DNA breaks in human lymphocytes subjected to hydrogen peroxide (H2O2) or gamma-rays (2 Gy dose). Lymphocytes were incubated with or without different concentrations of BTE (0.005-500 µg/ml) for 30 min, followed by treatment with or without H2O2 (0.088 µmol/l) for 5 min. To examine the radioprotective effect of BTE, the lymphocytes were incubated with or without BTE for 30 and 60 min prior to and following in vitro irradiation. Oxidative damage to DNA was monitored using a comet assay. BTE at lower concentrations prevented H2O2-induced DNA damage. An increase in BTE concentrations resulted in increased formation of single strand DNA breaks. BTE also exerted significant protective effects against gamma radiation-induced total DNA damage in healthy lymphocytes during their 30 or 60 min incubation with BTE prior to or following irradiation. Therefore, the protective effect of BTE against irradiation was time-dependent. The results contribute to the research on potential beneficial effects of natural compounds, such as BTE, in cancer and its protective effects of normal tissue during radiation therapy.

Yellow gentian root extract provokes concentration- and time-dependent response in peripheral blood mononuclear cells

“…G. dinarica extract elevated the frequency of micronuclei and enhanced apoptosis in peripheral blood lymphocytes ( 34 ). Similar results were found for many plant extracts known for their antioxidant activity and rich in polyphenols, such as black and green tea extract, suggesting that higher polyphenol concentrations could lead to spontaneous H 2 O 2 generation, DNA damage, and cell death ( 35 , 36 ). In line with this argument, the concentration determines whether certain compound or extract acts as anti- or pro-oxidant.…”

Radioprotective effects of lentil sprouts against X-ray radiation

“…These findings confirm the hypothesis that lentil sprout extract offers a protective effect against radiation by inhibition of ROS production. Although some plant such as Zataria multiflora ( 17 ) and black tea( 29 ) show more radioprotective effect, comparison to our result with studied cereal like wheat( 30 ) and legume like peanut( 31 ), lentil sprout demonstrated appropriate radioprotective efficiency. This study gives new insights into the role of lentil sprout extract in attenuating lymphocyte damage induced by radiation.…”

Dark tea extract mitigates hematopoietic radiation injury with antioxidative activity

“…Our results confirmed that DTE could decrease the ROS levels elevated by IR. In addition, DNA injury induced by IR was determined by H2AX phosphorylation, and this was used as an index for quantifying DNA double-strand breaks [ 33 – 36 ]. The data suggested that DTE could mitigate DNA injury induced by IR.…”