Tea Extract Prevents Arsenic-mediated DNA Damage and Death of Murine Thymocytes in vitro

Abstract

Groundwater contamination by arsenic has created a major health hazard in Bangladesh by affecting
millions of people. In this study, we report cytotoxic effects of arsenic in primary culture of murine thymocytes and
the counteractive actions of tea extract to reduce this cytotoxic effects. When murine thymocytes were incubated for
shorter period (1 h) with higher concentrations (50 and 100 μM) of sodium arsenite (NaAsO2), cell viability was
decreased to 79.06 ± 0.52% and 62.53 ± 0.23%, respectively. In case of longer incubation (16 hrs) with a wide range
of NaAsO2 concentration (1-100 μM), cell viability was reduced from 89.30 ± 0.84% to 79.0 ± 0.52% by 1 μM
NaAsO2, and this reduction was continued with increasing concentration reaching to 29.60 ± 0.72% by 100 μM. Tea
is known to possess antioxidant property and we found that this tea extract reduced NaAsO2-mediated death of the
cells in culture. After 16 h of incubation, the chromosomal DNA of 5 μM NaAsO2-exposed cells was found degraded
suggesting apoptotic death of the cells. Interestingly, this degradation of chromosomal DNA was blocked by tea
extract. All of these results together suggest a future therapeutic application of tea extract to reduce or block arsenic
toxicity.