RESUMEN
Objective: to study the efficacy of green tea extract against iron-induced oxidative stress, dyslipidemia and hormonal changes in rats compared with those of silymarin
Subjects: 54 adult male albino rats were divided into nine groups. The first three groups were considered as control groups [negative control C[1], silymarin control group C[2] and green tea control group C[3]]. The other three groups were treated with i.p. injection of ferrous sulphate [30 mg/ Kg/day]. The fourth group was considered as positive control [T[4]] while the fifth and sixth groups [T[5]andT[6]] received daily oral dose of silymarin [20 mg/kg/day] and green tea [2ml/rat/day], respectively, for ten consecutive days. The last three groups were fed the control diet for seven days, where the eighth and ninth groups were given daily oral dose of silymarin and green tea, respectively. On the seventh day, these groups were injected with a single i.p. dose of ferrous sulphate [300mg/Kg]. The seventh group was considered as positive control [T[7]] while the eighth and ninth groups [T[8]andT[9]] were continuously treated with the daily oral dose of silymarin and green tea. respectively for other three days. The experiment lasted for ten days
Methods: at the end of the experimental period, the blood samples were collected from all groups and blood hemoglobin level was estimated. Serum iron and total iron binding capacity [TIBC] were determined by spectrophotometric analysis and serum ferritin level was estimated using ELISA technique. Serum vitamin A and E as well as serum thiobarbituric acid reactive species [TBARS] levels were assayed. Serum total cholesterol, triacylglycerols [TAG] and HDL-Ch levels were also estimated. Serum creatine kinase MB [CK-ME] activity and troponin I levels were also determined. Plasma corticosterone and serum leptin levels were estimated using ELISA
Results: administration of green tea extract [GTE] to iron overloaded rats effectively decreased lipid peroxides to the same degree as silymarin. It significantly increased serum alpha-tocopherol level which was not changed by silymarin. Green tea extract decreased serum iron, ferrtin and hemoglobin as silymarin did when both agents were compared to the untreated iron overloaded rats. Regarding the lipid profile, administration of GTE to normal rats significantly decreased serum TAG compared to the control rats. For iron injected rats; GTE decreased TAG by 22.5%, while HDL-Ch level showed significant increase by GTE compared to untreated iron overloaded rats. Iron overload produced significant increase in creatine kinase MB [CK-MB] and slight increase in troponin I TnI s GTE administration, significantly decreased CK-MB and normalized TnI approximately to the same degree as silymarin. With respect to hormonal patterns, administration of GTE to iron overloaded rats like silymarin, induced slight decrease in corticosterone level compared to untreated rats. Although GTE caused no change in serum leptin for iron overloaded rats, it significantly decreased its level in normal rats [C3] compared to that of the control rats [C1]
Conclusion: in conclusion, green tea may exert its therapeutic role against oxidative stress produced by iron overload via its antioxidant properties , metal chelating activity, hypolipidemic action and hormone modulating capacity. Thus green tea extract possesses multifunctional manifestations