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Journal of Environmental Pathology, Toxicology and Oncology

ISSN for PRINT: 0731-8898

Institutional price:	$672.00
Issues per year:	4

Best Paper Award Selection - Editorial Board Site

2007, Volume26

82 pages

Issue price - $187.00

In Vitro Mitigation of Arsenic Toxicity by Tea Polyphenols in Human Lymphocytes

Dona Sinha
Department of Environmental Carcinogenesis & Toxicology, Chittaranjan National Cancer Institute, 37, S.P. Mukherjee Road, Kolkata 700026, India

Subhabrata Dey
Central Research Instrumentation Facility, Chittaranjan National Cancer Institute, 37, S.P. Mukherjee Road, Kolkata 700026, India

Rathindra Kumar Bhattacharya
Department of Environmental Carcinogenesis & Toxicology, Chittaranjan National Cancer Institute, 37, S.P. Mukherjee Road, Kolkata 700026, India

Madhumita Roy
Department of Environmental Carcinogenesis and Toxicology, Chittaranjan National Cancer Institute, Kolkata, India

ABSTRACT

The groundwater arsenicals have brought dreadful misery for the people residing in the endemic regions of West Bengal, India. Arsenic-related anomalies include arsenicosis, hyperkera-tosis, gastric complications, liver fibrosis, peripheral neuropathy, and cancer. Some of these diseases have been frequently associated with overproduction of reactive oxygen species that cause DNA damage and improper functioning of body's antioxidant defense mechanism. Natural polyphenols present in tea serve as excellent antioxidants. In the present study, an attempt has been made to elucidate the role of representative polyphenols and extracts of green and black tea in modulating sodium arsenite (As III)−induced DNA damage in normal human lymphocytes. Comet assay was used to detect the DNA damage. Arsenic-induced oxidative stress was measured with generation of reactive oxygen species, lipid peroxidation, and activity of some antioxidant enzymes. Expression of some repair enzymes such as poly(ADP-ribose) polymerase and DNA polymerase β was measured to assess the effect of tea on DNA repair. Tea afforded efficient reduction of As III−induced DNA damage in human lymphocytes. Tea also quenched the excessive production of reactive oxygen species by arsenic, reduced the elevated levels of lipid peroxidation, and increased the activity of antioxidant enzymes such as catalase, superoxide dismutase, and glutathione peroxidase. Furthermore, tea enhanced recovery of DNA damage, which was indicative of repair as confirmed by unscheduled DNA synthesis and pronounced expression of DNA repair enzyme poly(ADP-ribose) polymerase. It is speculated that the antioxidant potential and repair-inducing capacity of tea might help in combating the severe genotoxic effects induced by arsenic in the human population.