Superoxide dismutase, glutathione peroxidase, and glutathione reductase in sheep organs

The enzyme activities of the superoxide dismutase (SOD), glutathione peroxidase (GSHPx), glutathione reductase (GR) and thiobarbituric acid reactive substances (TBARS) content were measured in tissue extracts of the liver, kidney and lung of sheep in a nonpolluted control area (C), a polluted area pasture (PP) and those from polluted areas but fed in the laboratory with an experimental emission supplement diet (EEF). Compared with the control SOD, activity was significantly increased (1.75 times) only in the liver of the PP group. In the EEF group there was a tendency toward lower activities in all organs. The Cu,Zn-SOD isoenzymes pattern analyzed by isoelectrofocusing was different in the organs of the animals exposed to pollutants when compared with those of the controls. In the liver, two new isoenzymes with pI 5.30 and 5.70 were found in the PP group and an additional isoenzyme with pI 5.10 in the EEF group. The kidney isoenzymes with pl 5.30 and 5.40 were inhibited in the EEF group. In the lung, two new isoenzymes appeared with pl 5.30 and 5.40 in the PP group and two new isoenzymes with pI 6.10 and 6.50 in the EEF group. GSHPx activity was inhibited in the liver and kidney of the sheep exposed to pollutants. GR activity was significantly changed only in the liver. The activity in the PP group was 2.30 and 2.10 times higher than in the C and EEF groups, respectively. TBARS content was increased in the liver and kidney of the EEF group compared with the control.     

Hyperoxia results in transient oxidative stress and an adaptive response by antioxidant enzymes in goldfish tissues

The effects of hyperoxia on the status of antioxidant defenses and markers of oxidative damage were evaluated in goldfish tissues. The levels of lipid peroxides, thiobarbituric acid reactive substances, carbonyl proteins and the activities of some antioxidant enzymes were measured in brain, liver, kidney and skeletal muscle of goldfish, Carassius auratus L., over a time course of 3-12 h of hyperoxia exposure followed by 12 or 36 h of normoxic recovery. Exposure to high oxygen resulted in an accumulation of protein carbonyls in tissues throughout hyperoxia and recovery whereas lipid peroxides and thiobarbituric acid reactive substances accumulated transiently under short-term hyperoxia stress (3-6 h) but were then strongly reduced. This suggests that hyperoxia stimulated an enhancement of defenses against lipid peroxidation or mechanisms for enhancing the catabolism of peroxidation products. The activities of principal antioxidant enzymes, superoxide dismutase and catalase, were not altered under hyperoxia but catalase increased during normoxic recovery; activities may rise in anticipation of further hyperoxic excursions. In most tissues, the activities of glutathione-utilizing enzymes (glutathione peroxidase, glutathione-S-transferase, glutathione reductase) as well as glucose-6-phosphate dehydrogenase, were not affected under hyperoxia but increased sharply during normoxic recovery. Correlations between some enzyme activities and oxidative stress markers were found, for example, an inverse correlation was seen between levels of thiobarbituric acid reactive substances and glutathione-S-transferase activity in liver and catalase and glucose-6-phosphate dehydrogenase in kidney. The results suggest that liver glutathione-S-transferase plays an important role in detoxifying end products of lipid peroxidation accumulated under hyperoxia stress.     

Effect of clofibrate treatment on glutathione content and the activity of the enzymes related to peroxide metabolism in rat liver and heart

Clofibrate treatment was shown to increase the content of reduced glutathione in rat liver and kidney, but did not alter the glutathione level in heart, brain, spleen and small intestine. Clofibrate did not affect the activity of superoxide dismutase, glutathione peroxidase, glutathione reductase and glucose-6-phosphate dehydrogenase in rat liver and heart. The drug decreased the activity of glutathione-S-transferase in the cytosolic fraction of liver homogenate. Glutathione-S-transferase activity in small intestine was also reduced. The administration of clofibrate decreased the content of polypeptides with mol. wt of 22,000 and 24,000 (possible monomers of glutathione-S-transferase) in the cytosolic fraction of liver cells.     

A rapid purification procedure for camel kidney glutathione S-transferase

Glutathione S-transferase was isolated from supernatant of camel kidney homogenate centrifugation at 37,000 xg by glutathione agarose affinity chromatography. The enzyme preparation has a specific activity of 44 mumol/min/mg protein and recovery was more than 85% of the enzyme activity in the crude extract. Glutathione agarose affinity chromatography resulted in a purification factor of about 49 and chromatofocusing resolved the purified enzyme into two major isoenzymes (pI 8.7 and 7.9) and two minor isoenzymes (pI 8.3 and 6.9). The homogeneity of the purified enzyme was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration on Sephadex G-100. The different isoenzymes were composed of a binary combination of two subunits with molecular weight of 29,000 D and 26,000 D to give a native molecular weight of 55,000 D. The substrate specificities of the major camel kidney glutathione S-transferase isoenzymes were determined towards a range of substrates. 1-chloro-2,4-dinitrobenzene was the preferred substrate for all the isoenzymes. Isoenzyme III (pI 7.9) had higher specific activity for ethacrynic acid and isoenzyme II (pI 8.3) was the only isoenzyme that exhibited peroxidase activity. Ouchterlony double-diffusion analysis with rabbit antiserum prepared against the camel kidney enzyme showed fusion of precipitation lines with the enzymes from camel brain, liver and lung and no cross reactivity was observed with enzymes from kidneys of sheep, cow, rat, rabbit and mouse. Different storage conditions have been found to affect the enzyme activity and the loss in activity was marked at room temperature and upon repeated freezing and thawing.     

A Rapid Purification Procedure for Camel Kidney Glutathione S-Transferase

Glutathione S-transferase was isolated from supernatant of camel kidney homogenate centrifugation at 37, 000 xg by glutathione agarose affinity chromatography. The enzyme preparation has a specific activity of 44 μ;mol/min/mg protein and recovery was more than 85% of the enzyme activity in the crude extract. Glutathione agarose affinity chromatography resulted in a purification factor of about 49 and chromatofocusing resolved the purified enzyme into two major isoenzymes (pI 8.7 and 7.9) and two minor isoenzymes (pI 8.3 and 6.9). The homogeneity of the purified enzyme was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration on Sephadex G-100.

The different isoenzymes were composed of a binary combination of two subunits with molecular weight of 29, 000 D and 26, 000 D to give a native molecular weight of 55, 000 D.

The substrate specificities of the major camel kidney glutathione S-transferase isoenzymes were determined towards a range of substrates. l-chloro-2, 4-dinltrobenzene was the preferred substrate for all the isoenzymes. Isoenzyme III (pI 7.9) had higher specific activity for ethacrynic acid and isoenzyme II (pI 8.3) was the only isoenzyme that exhibited peroxidase activity. Ouchterlony double-diffusion analysis with rabbit antiserum prepared against the camel kidney enzyme showed fusion of precipitation lines with the enzymes from camel brain, liver and lung and no cross reactivity was observed with enzymes from kidneys of sheep, cow, rat, rabbit and mouse.

Different storage conditions have been found to affect the enzyme activity and the loss in activity was marked at room temperature and upon repeated freezing and thawing.     

Antioxidant and detoxifying fish enzymes as biomarkers of river pollution

The activity of several antioxidant and detoxifying enzymes, superoxide dismutase SOD, GSH peroxidase GSHPx, GSSG reductase GSR and GSH S transferase GST, the contents of thiobarbituric acid reactive substances TBARS, and the SOD and GST isoenzyme patterns were studied in the livers of chubs Leuciscus cephalus from reference river areas and polluted urban sites. Livers of polluted fish contained higher concentrations of transition metals, especially copper and iron. Total GSHPx activity was 1.8 fold higher in the polluted fish than in reference animals, while the SOD and GSR activities and the TBARS content were not significantly changed. Three new SOD isoforms pI 4.45, 5.1, 5.2 and a higher intensity of the band pI 4.2 were observed after isoelectrofocusing of polluted fish extracts. Total GST activity was higher in fish from polluted areas. The GST isoenzyme pattern was studied using subunit specific substrates DCNB, EPNP, EA, NPB, NBC and by Western blot using antibodies specific to rat GST subunits 1, 8 Alpha class, 3 Mu class and 7 Pi class. Reference and polluted fish lacked cross reactivity towards Alpha class GSTs. Reference fish displayed weaker cross reactivity towards CST 7 and 2.3 fold lower activity with EA, while higher cross reaction with GST 3 was observed in polluted fish.     

Antioxidant and detoxifying fish enzymes as biomarkers of river pollution

The activity of several antioxidant and detoxifying enzymes, superoxide dismutase SOD , GSH peroxidase GSHPx , GSSG reductase GSR and GSH S transferase GST , the contents of thiobarbituric acid reactive substances TBARS , and the SOD and GST isoenzyme patterns were studied in the livers of chubs Leuciscus cephalus from reference river areas and polluted urban sites. Livers of polluted fish contained higher concentrations of transition metals, especially copper and iron. Total GSHPx activity was 1.8 fold higher in the polluted fish than in reference animals, while the SOD and GSR activities and the TBARS content were not significantly changed. Three new SOD isoforms pI 4.45, 5.1, 5.2 and a higher intensity of the band pI 4.2 were observed after isoelectrofocusing of polluted fish extracts. Total GST activity was higher in fish from polluted areas. The GST isoenzyme pattern was studied using subunit specific substrates DCNB, EPNP, EA, NPB, NBC and by Western blot using antibodies specific to rat GST subunits 1, 8 Alpha class , 3 Mu class and 7 Pi class . Reference and polluted fish lacked cross reactivity towards Alpha class GSTs. Reference fish displayed weaker cross reactivity towards CST 7 and 2.3 fold lower activity with EA, while higher cross reaction with GST 3 was observed in polluted fish.     

Antioxidant role of coumarin on streptozotocin-nicotinamide-induced type 2 diabetic rats

The purpose of this study was to investigate the antioxidant role of coumarin on streptozotocin-nicotinamide-induced Type 2 diabetic rats. In experimental rats, the levels of plasma glucose, insulin, and the levels of thiobarbituric acid reactive substances, lipid hydroperoxides, conjugated dienes, and the activities of superoxide dismutase, catalase, glutathione-S-transferase, and glutathione peroxidase were assayed in liver and kidney. Diabetic rats showed elevated levels of plasma glucose and lipid peroxidation markers and reduced plasma insulin and antioxidant enzymes. Oral administration of coumarin resulted in a significant reduction in the plasma glucose and lipid peroxides and a significant increase in the plasma insulin and antioxidant enzymes. Chronic treatment of coumarin remarkably restored the normal status of the histopathological changes observed in the selected tissues. It can be concluded that coumarin has antioxidant effect in Type 2 diabetic rats.     

Acute lindane intoxication: A study on lindane tissue concentration and oxidative stress-related parameters in liver and erythrocytes

Treatment of rats with daily dosis of 20 mg of lindane/kg for 3 consecutive days led to the accumulation of the insecticide in several tissues, including erythrocytes and liver. Lindane did not alter the hematocrit and hemoglobin concentration but reduced methemogiobin levels by 17%. Red blood cells from controls and lindane-treated rats, exposed to t-butyl hydroperoxide, exhibited comparable rates of oxygen uptake and visible chemiluminescence, whereas the induction period that precedes oxygen uptake was significantly enhanced in the latter group. Lindane treatment did not modify the activity of erythrocyte glutathione peroxidase, glucose-6-phosphate dehydrogenase, catalase, and methemoglobin reductase, being the total content of glutathione and superoxide dismutase activity significantly increased. The liver from lindane-treated rats showed an enhanced microsomal pro-oxidant activity, evidenced by higher cytochrome P450 content and NADPH-cytochrome c reductase and NADPH oxidase activities. The higher enzyme activities led to an increased superoxide anion generation (adrenochrome formation) and lipid peroxidation (measured either by the production of thiobarbituric acid reactants and spontaneous visible chemiluminescence). Concomitantly, liver glutathione content and the activity of glutathione peroxidase-glutathione reductase couple were augmented by lindane treatment, without any change in superoxide dismutase activity, together with a reduction in that of catalase. Results suggest that lindane does not alter the prooxidant/antioxidant status of the erythrocyte in conditions of a significant cellular accumulation of the insecticide, which might exert direct action on enzymatic systems leading to enhanced superoxide dismutase activity and glutathione content. In the liver, lindane-induced pro-oxidant condition was not accompanied by cell injury, probably due to the adaptative increase in some antioxidant mechanisms of the hepatocyte.     

Antioxidant effect of tetrahydrocurcumin in streptozotocin-nicotinamide induced diabetic rats

Oxidative stress has been suggested to be a contributory factor in development and complication of diabetes. In the present study, we have investigated the effect of tetrahydrocurcumin (THC), one of the active metabolites of curcumin on antioxidants status in streptozotocin-nicotinamide induced diabetic rats. Oral administration of THC at 80 mg/kg body weight of diabetic rats for 45 days resulted in significant reduction in blood glucose and significant increase in plasma insulin levels. In addition, THC caused significant increase in the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, reduced glutathione, vitamin C and vitamin E in liver and kidney of diabetic rats with significant decrease in thiobarbituric acid reactive substances (TBARS) and hydroperoxides formation in liver and kidney, suggesting its role in protection against lipid peroxidation induced membrane damage. These biochemical observations were supplemented by histopathological examination of liver and kidney section. The antidiabetic and antioxidant effects of THC are more potent than those of curcumin at the same dose. Results of the present study indicated that THC showed antioxidant effect in addition to its antidiabetic effect in type 2 diabetic rats.     

Glutathione and ascorbic acid metabolism and antioxidant enzyme activity in the tissues of vitamin E-deficient rats

In has been shown in the experiments on male rats that alimentary vitamin E deficit causes the decrease of reduced glutathione and ascorbic acid concentration in the liver and lungs and that of glutathione-S-transferase, glutathione reductase in the liver and lungs, catalase in the liver and glutathione peroxidase in the heart activity, but increases the amount of glutathione disulfide in the liver and lungs and superoxide dismutase and gamma-glutamyltransferase activity in the liver. The data obtained show the selective character of reaction participants of the antioxidant system of rats' organism to the deficit of one of the antioxidant factors--vitamin E and also testify to complex interrelation between separate members of this system.     

Antidiabetic effect of Scoparia dulcis: effect on lipid peroxidation in streptozotocin diabetes

Oxidative damage has been suggested to be a contributory factor in the development and complications of diabetes. The antioxidant effect of an aqueous extract of Scoparia dulcis, an indigenous plant used in Ayurvedic medicine in India was studied in rats with streptozotocin-induced diabetes. Oral administration of Scoparia dulcis plant extract (SPEt) (200 mg/kg body weight) for 3 weeks resulted in a significant reduction in blood glucose and an increase in plasma insulin. The aqueous extract also resulted in decreased free radical formation in tissues (liver and kidney) studied. The decrease in thiobarbituric acid reactive substances (TBARS) and hydroperoxides (HPX) and increase in the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH) and glutathione-S-transferase (GST) clearly show the antioxidant properties of SPEt in addition to its antidiabetic effect. The effect of SPEt at 200 mg/kg body weight was better than glibenclamide, a reference drug.     

Effect of chlorpyrifos on thiobarbituric acid reactive substances, scavenging enzymes and glutathione in rat tissues

The present study showed that exposure of chlorpyrifos, O,O'-diethyl-O-3,5,6-trichloro-2-pyridyl phosphorothionate (CPF), a widely used pesticide in rats caused significant inhibition of acetylcholinesterase (AChE) activity in different tissues viz., liver, kidney and spleen. CPF exposure also generated oxidative stress in the body, as evidenced by increase in thiobarbituric acid reactive substances (TBARS), decrease in the levels of superoxide scavenging enzymes viz., superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in liver, kidney and spleen at all doses. Malondialdehyde levels were increased by 14%, 31% and 76% in liver, 11%, 31% and 64% in kidney and 32%, 75% and 99.9% in spleen when 50 mg, 100 mg and 200 mg/kg body wt. CPF was administered for three days. SOD and CAT activities were decreased in liver, kidney and spleen, while GPx activity showed slight increase in kidney at 50 mg and 100 mg dose, and decreased on further increase in dose of CPF. Liver and spleen showed dose-dependent decrease in GPx activity. The levels of reduced glutathione (GSH) was decreased, while oxidized glutathione (GSSG) was increased, thus a marked fall in GSH/GSSG ratio was observed in all tissues. A maximum decrease of 83% was observed in liver, followed by kidney and spleen, which showed 78% and 57% decrease, respectively in group given 200 mg/kg CPF. The levels of glucose-6-phosphate dehydrogenase (G6PDH) and glutathione reductase (GR) were also decreased in liver and kidney, while spleen showed increase at lower doses, but decrease at high dose of CPF. The data provide evidence for induction of oxidative stress on CPF exposure.     

Hepatoprotective effects of saponarin, isolated from Gypsophila trichotoma Wend. on cocaine-induced oxidative stress in rats

The antioxidant effect of saponarin, which is the main flavone isolated from Gypsophila trichotoma Wend., and its protection against cocaine hepatotoxicity were investigated in male Wistar rats. The animals were treated with cocaine (40 mg/kg i.p.) alone and also after 3 consecutive days of pretreatment with saponarin (80 mg/kg p.o.). After 18 hours the rats were sacrificed by decapitation. The production of thiobarbituric acid reactive substances, reduced glutathione (GSH) and the activity of the following antioxidant enzymes: catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase were assessed in liver homogenate. Administered alone, cocaine induced significant hepatotoxicity manifested with GSH depletion and reduced antioxidant defences. Saponarin pretreatment, however, decreased cocaine toxicity both by increasing GSH levels and antioxidant enzyme activities. The results of this study proved the antioxidant activity of saponarin and its protective effect against cocaine-induced oxidative stress and hepatotoxicity.     

The effect of lycopene on oxytetracycline-induced oxidative stress and immunosuppression in rainbow trout (Oncorhynchus mykiss, W.)

The aim of this study was to determine the effects of lycopene on oxytetracycline (OTC)-induced oxidative stress and immunosuppression in rainbow trout. The experimental fish analysed in this study were divided into 6 different experimental groups. Group 1 was the control group, and groups 2, 3 and 4 received corn oil, lycopene and OTC, respectively, for 14 days. Group 5 received OTC for 14 days after lycopene pre-treatment for 14 days, while group 6 received OTC for 14 days before lycopene post-treatment for 14 days. Blood and tissue samples were collected at the end of the experiment and analysed for the oxidant-antioxidant status and changes in the immune response. There was a significant increase in the malondialdehyde level, which is an index of lipid peroxidation, and a decrease in superoxide dismutase, catalase, and glutathione peroxidase activity as well as a decrease in the glutathione level in the blood, liver, kidney and spleen of OTC-treated fish. Glutathione-S-transferase activity was significantly increased in the blood, liver, kidney and spleen samples of the group that received OTC alone. OTC also appeared to suppress specific and nonspecific immune system parameters, such as the haematocrit, leucocyte count, oxidative radical production (nitroblue tetrazolium activity), total plasma protein and immunoglobulin levels and phagocytic activity. Pre- and post-treatment with lycopene attenuated the OTC-induced oxidative stress by significantly decreasing the tissue malondialdehyde level. The superoxide dismutase, catalase and glutathione peroxidase activities as well as the glutathione levels were significantly increased with lycopene administration, while glutathione-S-transferase activity was significantly decreased. Lycopene administration was also associated with a significant increase in the OTC-suppressed immune system parameters in fish. Thus, the present results suggest that pre- and post-treatment with lycopene (10 mg per kg fish weight, delivered orally) may alleviate OTC-induced oxidative stress and immunosuppression.     

Activation of peroxisomal acyl-CoA oxidase and lipid peroxidation in the rat myocardium as affected by prolonged administration of ethanol

The influence of chronic alcoholic intoxication on the activity of peroxisomal acyl-CoA oxidase and antioxidative defensive enzymes (catalase, glutathione reductase, glutathione-S-transferase, superoxide dismutase, glucose-6-phosphate dehydrogenase) was studied in the rat myocardium. The parameters of lipid peroxidation in cardiomyocytes (the level of spontaneous chemiluminescence, accumulation of thiobarbituric acid-reactive material), as well as reduced glutathione content were also examined. The data obtained suggest that ethanol-induced activation of lipid peroxidation in the myocardium may be due to the elevation of hydrogen peroxide-generating activity of peroxisomes.     

Developmental Aspects of Detoxifying Enzymes in Fish (Salmo Iridaeus)

The activities of superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase, glutathione transferase and glyoxalase I have been studied during the embryologic development of rainbow trout (Salmo iridaeus) and in several other trout tissues to investigate the protective development metabolism.

A gradual increase of superoxide dismutase, catalase, glutathione reductase, glyoxalase I and glutathione transferase activities was noted throughout embryo development.

In all trout tissues investigated glutathione peroxidase was found to be extremely low compared to catalase activity. The highest activity of superoxide dismutase, glyoxalase I and glutathione reductase was found in liver followed by kidney.

No change in the number of GST subunits was noted with the transition from the embryonic to the adult stages of life according to the SDS/PAGE and HPLC analyses performed on the GSH-affinity purified fractions.     

Effect of pineal indoles on activities of the antioxidant defense enzymes superoxide dismutase, catalase, and glutathione reductase, and levels of reduced and oxidized glutathione in rat tissues.

Male Sprague-Dawley rats were randomly divided into four groups. Two of the groups received a single intraperitoneal injection of melatonin and 5-methoxytryptamine (5 mg/kg body weight), respectively, at 9 PM. One group received an intraperitoneal injection of 5-methoxytryptophol (5 mg/kg body weight) at 9 AM. The remaining group received alcoholic saline (vehicle) and served as the control. All rats were sacrificed 90 min after injection and the livers, kidneys, and brains were dissected. The activities of superoxide dismutase, catalase, and glutathione reductase in the organs were measured. It was found that both melatonin and 5-methoxytryptamine were approximately equipotent in enhancing the activities of superoxide dismutase and glutathione reductase in the kidney and liver, while 5-methoxytryptophol displayed a weaker effect. Both melatonin and 5-methoxytryptamine augmented the level of reduced glutathione in the kidney and liver, while 5-methoxytryptophol did so only in the kidney. All three pineal indoles increased the activity of superoxide dismutase and lowered the ratio of oxidized to reduced glutathione in the brain.     

Lipid peroxidation and activity of antioxidant enzymes in diabetic rats

We hypothesized that oxygen free radicals (OFRs) may be involved in pathogenesis of diabetic complications. We therefore investigated the levels of lipid peroxidation by measuring thiobarbituric acid reactive substances (TBARS) and activity of antioxidant enzymes [superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT)] in tissues and blood of streptozotocin (STZ)-induced diabetic rats. The animals were divided into two groups: control and diabetic. After 10 weeks (wks) of diabetes the animals were sacrificed and liver, heart, pancreas, kidney and blood were collected for measurement of various biochemical parameters. Diabetes was associated with a significant increase in TBARS in pancreas, heart and blood. The activity of CAT increased in liver, heart and blood but decreased in kidney. GSH-Px activity increased in pancreas and kidney while SOD activity increased in liver, heart and pancreas. Our findings suggest that oxidative stress occurs in diabetic state and that oxidative damage to tissues may be a contributory factor in complications associated with diabetes.     

Antiperoxidative and antioxidant effects of Casearia esculenta root extract in streptozotocin-induced diabetic rats

Oxidative stress is currently suggested to play as a pathogenesis in the development of diabetes mellitus. The present study was designed to evaluate the effect of Casearia esculenta root extract on oxidative stress-related parameters in streptozotocin (STZ) -induced diabetic rats. Antidiabetic treatment with C. esculenta root extract (45 days) significantly (p < .05) decreased thiobarbituric acid reactive substances (TBARS) and remarkably improved tissue antioxidants status such as glutathione (GSH), ascorbic acid (vitamin C) and alpha-tocopherol (vitamin E) in liver and kidney of STZ-diabetic rats. In diabetics rats, the activities of enzymatic antioxidants such as superoxide dismutase (SOD, EC 1.11.1.1) catalase (CAT, EC 1.11.1.6) were decreased significantly while the activity of glutathione peroxidase (GPx, EC 1.11.1.9) decreased in the liver and increased in the kidney. The treatment of diabetic rats with C. esculenta root extract over a 45-day period returned these levels close to normal. These results suggest that C. esculenta root extracts exhibit antiperoxidative as well as antioxidant effects in STZ-induced diabetic rats.