Pesticide-induced alteration in mice hepato-oxidative status and protective effects of black tea extract.

BACKGROUND: This study investigates the role of black tea extract in protection against oxidative damage induced in mice by a subacute oral dose of a combination of pesticides.
METHODS: Liver damage markers like amino-acid transferases and alkaline phosphatase, oxidative damage markers indicating extent of lipid peroxidation, host antioxidant reserve indicators like reduced glutathione (GSH) and total thiol levels, GSH-dependent enzyme activities viz., glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione reductase (GR) superoxide dismutase (SOD) and catalase (CAT) were measured by spectrophotometric techniques in four different groups namely (1) control, (2) black tea extract, (3) pesticide alone and (4) pretreatment with black tea extract followed by pesticide treatment.
RESULTS: Following exposure to pesticides lipid peroxidation was increased compared to that in the control [0.50+/-0.083 (mean+/-S.E.) vs. 0.21+/-0.02 micromol/mg protein, p<0.001]. Moreover, levels of antioxidants like GSH and total thiol were also significantly decreased in comparison to control, e.g., GSH [5.16+/-0.78 vs. 6.96+/-1.35 micromol/mg protein, p<0.001], total thiol [19.3+/-2.74 vs. 26.15+/-2.8 micromol/mg protein, p<0.001]. In addition, the activities of antioxidant enzymes like GPx, GST, GR, SOD and catalase were also likewise diminished by oxidant damage. Treatment with aqueous black tea extract significantly protects the liver tissue from the oxidative damage and shifts the trend towards amelioration and replenishment of the antioxidant status.
CONCLUSIONS: The active components present in natural extracts like that of black tea can be very effective in perhaps reducing the extent of injury and in overcoming oxidant damage caused by exposure to environmental agents like pesticides.