Parameters related to oxygen free radicals in erythrocytes,plasma and epidermis of the hairless rat

The following parameters related to oxygen free radicals (OFR) were determined in erythrocytes and the epidermis of hairless rats: catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), reduced (GSH) and oxidized (GSSG) glutathione, glutathione S-transferase (GST), superoxide dismutase (SOD) and thiobarbituric acid reactive substances (TBARS). GSH, GSSG and TBARS were also analyzed in plasma. In erythrocytes, the Pearson correlation coefficients (r) were significant (p < 0.001) between glutathione and other parameters as follows: GSH correlated negatively with GSSG (r = -0.665) and TBARS (r = -0.669); GSSG correlated positively with SOD (r = 0.709) and TBARS (r = 0.752). Plasma GSSG correlated negatively with erythrocytic thermostable GST activity (r = -0.608; p=0.001) and with erythrocytic total GST activity (r = -0.677; p < 0.001). In epidermis (p < 0.001 in all cases), GSH content correlated with GSSG (r = 0.682) and with GPx (r = 0.663); GSSG correlated with GPx (r = 0.731) and with GR (r = 0.794). By multiple linear regression analysis some predictor variables (R(2)) were found: in erythrocytes, thermostable GST was predicted by total GST activity and GSSG, GSSG content was predicted by GSH and by the GSH/GSSG ratio and GPx activity was predicted by GST, CAT and SOD activities; in epidermis, GSSG was predicted by GR and SOD activities and GR was predicted by GSSG, TBARS and GPx. It is concluded that the hairless rat is a good model for studying OFR-related parameters simultaneously in blood and skin, and that it may provide valuable information about other animals under oxidative stress.     

24-hour rhythms in oxidative stress during hepatocarcinogenesis in rats: effect of melatonin or alpha-ketoglutarate

To compare the effects of alpha-ketoglutarate (alpha-KG) and melatonin on 24-h rhythmicity of oxidative stress in N-nitrosodiethylamine (NDEA)-injected Wistar male rats, melatonin (5 mg/kg i.p.) or alpha-KG (2 g/kg through an intragastric tube) was given daily for 20 weeks. In blood collected at 6 time points during a 24-h period, serum activity of aspartate transaminase (AST) and alanine transaminase (ALT) and the levels of alpha-fetoprotein (alpha-FP) were measured as markers of liver function. To assess lipid peroxidation and the antioxidant status, plasma levels of thiobarbituric acid reactive substances (TBARS) and of reduced glutathione (GSH) were measured, together with the activity of erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST). NDEA augmented mesor and amplitude of rhythms in AST and ALT activity and plasma alpha-FP levels and mesor values of plasma TBARS, while decreasing mesor values of plasma GSH and erythrocyte SOD, CAT, GPx and GST. Acrophases were delayed by NDEA in all cases except for alpha-FP rhythm, which became phase-advanced. Co-administration of melatonin or alpha-KG partially counteracted the effects of NDEA. Melatonin decreased mesor of plasma TBARS and augmented mesor of SOD activity. The results indicate that melatonin and alpha-KG are effective in protecting from NDEA-induced perturbation of 24-h rhythms in oxidative stress. Melatonin augmented antioxidant defense in rats.     

Protective effect of black tea extract on the levels of lipid peroxidation and antioxidant enzymes in liver of mice with pesticide-induced liver injury

Sub-acute hepatotoxicity was induced in mice by exposure to pesticides. The effect of pretreatment with aqueous black tea extract on lipid peroxidation and antioxidants in the liver was investigated. Administering a combination dose of chlorpyriphos and cypermethrin (20 mg kg(-1) each) on alternate days over a 15-day period to male mice resulted in induction of sub-acute toxicity as reflected by elevated levels of liver damage marker enzymes alkaline phosphatase(ALP), aspartate transaminase(AST) and alanine transaminase(ALT). Significantly elevated levels of lipid peroxidation were observed in the experimental group (group III) as compared with control mice. Decreased activities of superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), total thiol, glutathione peroxidase (GPx), glutathione reductase(GR) and glutathione-S-transferase (GST) were also observed in pesticide-treated as compared to control mice. Aqueous black tea extract was given as a pretreatment to group IV mice at a dose of 200 mg ml(-1) polyphenols before the pesticide dose, which significantly decreased the levels of lipid peroxidation and significantly elevated the activities of SOD, CAT, GSH, total thiol, GPx, GR and GST in liver to levels similar to the controls. Thus, the data offer support for the claim that the central mechanism of pesticide action occurs via changes in cellular oxidative status and shows conclusively that supplementation with black tea extract protects against the free radical-mediated oxidative stress in hepatocytes of animals with pesticide-induced liver injury.     

Impact of Hemidesmus indicus R.Br. extract on ethanol-mediated oxidative damage in rat kidney

The antioxidant effect of the ethanolic extract of Hemidesmus indicus R.Br. root (EHI), an indigenous Ayurvedic medicinal plant in India, was studied in rats with ethanol-induced nephrotoxicity. Administering 5 g/kg body weight/day of ethanol for 60 days to male Wistar rats resulted in significantly elevated levels of serum urea, creatinine and uric acid as well as kidney thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides (LOOH) and conjugated dienes (CD) as compared to those of the experimental control rats. Decreased levels of kidney superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), vitamin C and vitamin E were also observed on alcohol administration as compared with those of the experimental control rats. EHI was administered at a dose of 500 mg/kg body weight/day for the last 30 days of the experiment to rats with ethanol-induced kidney injury, which significantly decreased the levels of serum urea, uric acid and creatinine as well as kidney TBARS, LOOH and CD and significantly elevated the activities of SOD, CAT, GPx, GSH, vitamin C and vitamin E in kidney as compared to that of untreated ethanol-administered rats. Histopathological observations also correlated with the biochemical parameters. Thus, the data indicate that treatment with EHI offers protection against free radical-mediated oxidative stress in kidney of animals with ethanol-induced nephrotoxicity.     

Antioxidant efficacy of black pepper (Piper nigrum L.) and piperine in rats with high fat diet induced oxidative stress

The present study was aimed to explore the effect of black pepper (Piper nigrum L.) on tissue lipid peroxidation, enzymic and non-enzymic antioxidants in rats fed a high-fat diet. Thirty male Wistar rats (95-115 g) were divided into 5 groups. They were fed standard pellet diet, high-fat diet (20% coconut oil, 2% cholesterol and 0.125% bile salts), high-fat diet plus black pepper (0.25 g or 0.5 g/kg body weight), high-fat diet plus piperine (0.02 g/kg body weight) for a period of 10 weeks. Significantly elevated levels of thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD) and significantly lowered activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and reduced glutathione (GSH) in the liver, heart, kidney, intestine and aorta were observed in rats fed the high fat diet as compared to the control rats. Simultaneous supplementation with black pepper or piperine lowered TBARS and CD levels and maintained SOD, CAT, GPx, GST, and GSH levels to near those of control rats. The data indicate that supplementation with black pepper or the active principle of black pepper, piperine, can reduce high-fat diet induced oxidative stress to the cells.     

Impact of Hemidesmus indicus R.Br. extract on ethanol-mediated oxidative damage in rat kidney

Abstract

The antioxidant effect of the ethanolic extract of Hemidesmus indicus R.Br. root (EHI), an indigenous Ayurvedic medicinal plant in India, was studied in rats with ethanol-induced nephrotoxicity. Administering 5 g/kg body weight/day of ethanol for 60 days to male Wistar rats resulted in significantly elevated levels of serum urea, creatinine and uric acid as well as kidney thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides (LOOH) and conjugated dienes (CD) as compared to those of the experimental control rats. Decreased levels of kidney superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), vitamin C and vitamin E were also observed on alcohol administration as compared with those of the experimental control rats. EHI was administered at a dose of 500 mg/kg body weight/day for the last 30 days of the experiment to rats with ethanol-induced kidney injury, which significantly decreased the levels of serum urea, uric acid and creatinine as well as kidney TBARS, LOOH and CD and significantly elevated the activities of SOD, CAT, GPx, GSH, vitamin C and vitamin E in kidney as compared to that of untreated ethanol-administered rats. Histopathological observations also correlated with the biochemical parameters. Thus, the data indicate that treatment with EHI offers protection against free radical-mediated oxidative stress in kidney of animals with ethanol-induced nephtrotoxicity.     

Ameliorative potential of S-allyl cysteine on oxidative stress in STZ induced diabetic rats

Increased oxidative stress and impaired antioxidant defense mechanism are important factors in the pathogenesis and progression of diabetes mellitus and other oxidant-related diseases. The present study was undertaken to evaluate the possible protective effects of S-allyl cysteine (SAC) against oxidative stress in streptozotocin (STZ) induced diabetic rats. SAC was administered orally for 45 days to control and STZ induced diabetic rats. The effects of SAC on glucose, plasma insulin, thiobarbituric acid reactive substances (TBARS), hydroperoxide, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), oxidized glutathione (GSSG) and GSH/GSSG ratio were studied. The levels of glucose, TBARS, hydroperoxide, and GSSG were increased significantly whereas the levels of plasma insulin, reduced glutathione, GSH/GSSG ratio, superoxide dismutase, catalase and GPx were decreased in STZ induced diabetic rats. Administration of SAC to diabetic rats showed a decrease in plasma glucose, TBARS, hydroperoxide and GSSG. In addition, the levels of plasma insulin, superoxide dismutase, catalase, GPx and reduced glutathione (GSH) were increased in SAC treated diabetic rats. The above findings were supported by histological observations of the liver and kidney. The antioxidant effect of SAC was compared with glyclazide, a well-known antioxidant and antihyperglycemic drug. The present study indicates that the SAC possesses a significant favorable effect on antioxidant defense system in addition to its antidiabetic effect.     

Activity of Cassia auriculata leaf extract in rats with alcoholic liver injury

This study was undertaken to investigate the effect of Cassia auriculata leaf extract on tissue lipid peroxidation and antioxidant status in experimental hepatotoxicity. Administering ethanol to rats for 60 days resulted in significantly elevated levels of serum total bilirubin, aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP) as compared with those of the experimental control rats. Significantly elevated levels of tissue thiobarbituric acid reactive substances (TBARS), hydroperoxides and lowered activities of superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) were also observed on alcohol treatment as compared with those of experimental control rats. Concentration of serum non-enzymic antioxidants such as vitamin E and vitamin C were also significantly lowered on alcohol supplementation. Treatment with Cassia auriculata leaf extract at a dose of 250 mg kg(-1) body weight and 500 mg kg(-1) body weight to rats administered alcohol, lowered the levels of TBARS and hydroperoxides and elevated the activities of SOD and CAT and the levels of reduced GSH in the liver, brain, kidney and intestine significantly compared to unsupplemented alcohol treated rats. Cassia auriculata leaf extract treatment restored the serum vitamin E, and vitamin C levels also to near those of the experimental control animals. Our data indicate that supplementation with Cassia auriculata leaf extract can offer protection against free radical mediated oxidative stress in experimental hepatotoxicity. In addition, histopathological studies of the liver and brain confirmed the beneficial role of Cassia auriculata leaf extract.     

Modulatory influence of dietary resveratrol during different phases of 1,2-dimethylhydrazine induced mucosal lipid-peroxidation, antioxidant status and aberrant crypt foci development in rat colon carcinogenesis

To shed light on the association of lipid peroxidation and antioxidant status with the development of aberrant crypt foci (ACF), we studied the modulatory influence of resveratrol, supplemented in three dietary regimens (initiation, post-initiation and entire period) on 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis. Rats were administered DMH (20 mg/kg body weight, s.c.) for 15 weeks and were supplemented with resveratrol (8 mg/kg body weight, p.o. everyday) in three dietary regimens. Intestines and colons were analyzed for the levels of diene conjugates (DC), lipid hydroperoxides (LOOHs) and thiobarbituric acid reactive substances (TBARS). Enzymic antioxidants (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPX; glutathione S-transferase, GST; and glutathione reductase, GR) and non-enzymic reserve (reduced glutathione, GSH; ascorbate; and alpha-tocopherol) were also assessed in the intestine and colon. Unsupplemented DMH exposed rats showed significantly decreased levels/activities of tissue DC, LOOHs, TBARS, SOD, CAT, GSH, GR and significantly elevated (P<0.05) GPX, GST, alpha-tocopherol and ascorbate as compared to control rats. Resveratrol supplementation during the entire period of the study resulted in significant (P<0.01) modulation of lipid peroxidation markers and antioxidants status, which were paralleled with ACF suppression, as compared to DMH-alone treated rats. These results indicate that resveratrol effectively inhibits DMH-induced ACF and colonic tumor development.     

Protective effect of resveratrol and vitamin E against ethanol-induced oxidative damage in mice: biochemical and immunological basis

The metabolism of ethanol gives rise to the generation of excess amounts of reactive oxygen species and is also associated with immune dysfunction. We examined the efficacy of resveratrol and vitamin E on the immunomodulatory activity and vascular function in mice with liver abnormalities induced by chronic ethanol consumption by measuring the protein, liver-specific transaminase enzymes, antioxidant enzymes and non-enzymes such as reduced glutathione (GSH) content, thiobarbituric acid reactive substance (TBARS) level, nitrite level, and activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GPx) and glutathione-S-transferase (GST), and cytokines such as interleukin (IL)-2, IL-4, IL-10, tumor necrosis factor (TNF)-alpha, gamma interferon (IFN-gamma), vascular endothelial growth factor (VEGF)-A and transforming growth factor (TGF)-beta1 in mice blood. Ethanol (1.6 g/kg body wt/day) exposure for 12 wks significantly increased TBARS and nitrite levels and GST activity, and significantly decreased GSH content and the activities of SOD, CAT, GR and GPx in whole blood hemolyzate of 8-10 wks-old male BALB/c mice (weighing 20-30 g). Ethanol exposure also elevated the activities of transaminase enzymes (AST and ALT), IL-10, TNF-alpha, IFN-gamma, VEGF-A and TGF-beta1, while decreasing the albumin concentration and IL-4 activity in the serum. Both resveratrol (5 mg kg(-1) day(-1)) and vitamin E (80 mg kg(-1) day(-1)) treatment significantly reduced AST, ALT, GST, IL-10, TNF-alpha, IFN-gamma, VEGF-A and TGF-beta1 activities and levels of TBARS and nitrite, and elevated albumin content, GSH level and activities of SOD, CAT, GR and GPx, compared to ethanol-treated group. Thus, results from the study demonstrated that both resveratrol (5 mg kg(-1) day(-1)) and vitamin E (80 mg kg(-1) day(-1)) can effectively ameliorate ethanol (1.6 g kg(-1) day(-1))-induced oxidative challenges, immunomodulatory activity and angiogenesis processes.     

Beneficial effect of succinic acid monoethyl ester on erythrocyte membrane bound enzymes and antioxidant status in streptozotocin-nicotinamide induced type 2 diabetes

Succinic acid monoethyl ester (EMS) was recently proposed as an insulinotropic agent for the treatment of non-insulin dependent diabetes mellitus. In the present study the effect of EMS and metformin on erythrocyte membrane bound enzymes and antioxidants activity in plasma and erythrocytes of streptozotocin-nicotinamide induced type 2 diabeteic model was investigated. Succinic acid monoethyl ester was administered intraperitonially for 30 days to control and diabetic rats. The effect of EMS on glucose, insulin, hemoglobin, glycosylated hemoglobin, TBARS, hydroperoxide, superoxide dismutase (SOD), catalase (CAT), glutathione peroxide (Gpx), glutathione-S-transferase (GST), vitamins C and E, reduced glutathione (GSH) and membrane bound enzymes were studied. The effect of EMS was compared with metformin, a reference drug. The levels of glucose, glycosylated hemoglobin, TBARS, hyderoperoxide, and vitamin E were increased significantly whereas the level of insulin and hemoglobin, as well as antioxidants (SOD, CAT, Gpx, GST, vitamin C and GSH) membrane bound total ATPase, Na(+)/K(+)-ATPase, Ca(2+)-ATPase and Mg(2+)-ATPase were decreased significantly in streptozotocin-nicotinamide diabetic rats. Administration of EMS to diabetic rats showed a decrease in the levels of glucose, glycosylated hemoglobin, lipid peroxidation markers and vitamin E. In addition the levels of insulin, hemoglobin, enzymic antioxidants, vitamin C, and GSH and the activities of membrane bound enzymes also were increased in EMS and metformin treated diabetic rats. The present study indicates that the EMS possesses a significant beneficial effect on erythrocyte membrane bound enzymes and antioxidants defense system in addition to its antidiabetic effect.     

Two cinnamate derivatives produce similar alteration in mRNA expression and activity of antioxidant enzymes in rats

Cinnamate is a widespread secondary metabolite of phenolic compound synthesized by plants for defensive purposes. The current study was designed to investigate the effect of two structurally related cinnamate derivatives, 4-hydroxycinnamate and 3-(4-hydroxyphenyl)propionic acid (HPP), on the mRNA expression and activity of antioxidant enzymes in high-cholesterol-fed rats. Male rats were fed a 1 g/100 g high-cholesterol diet with supplements of either 4-hydroxycinnamate or HPP (0.135 mmol/100 g diet) for 6 weeks. The plasma paraoxonase activity was found to be higher in the cinnamate-derivative-supplemented groups than in the control group. The erythrocyte superoxide dismutase (SOD) and catalase (CAT) activities, plus glutathione (GSH) level, were all significantly higher in the 4-hydroxycinnamate- and HPP-supplemented groups than in the control group. However, both 4-hydroxycinnamate and HPP supplementation significantly lowered the hepatic activities and mRNA expression of CAT and glutathione peroxidase (GSH-Px) compared to the control group. The hepatic mRNA expression and activity of SOD did not differ between the groups. The hepatic thiobarbituric acid reactive substances (TBARS) level was significantly lowered by the 4-hydroxycinnamate and HPP supplementation. Accordingly, these results indicate that supplementation by 4-hydroxycinnamate and HPP would seem to enhance the antioxidative defense of erythrocyte. Both HPP and 4-hydroxycinnamate would appear to be beneficial in improving the function of antioxidative enzymes on a molecular level in high-cholesterol-fed rats.     

Effects of Bacillus thuringiensis toxin on hepatic lipid peroxidation and free-radical scavengers in rats given alpha-tocopherol or acetylsalicylate

The effect of Dipel (D), a Bacillus thuringiensis-based bioinsecticide, on hepatic antioxidant enzyme activities and lipid peroxidation in rat liver was investigated. Administration of D in a dose of 1 mg/100 g body mass for 4 successive days increased the activities of glutathione peroxidase (GPx), glutathione reductase (GR) and the level of malondialdehyde (MDA) in rat hepatocytes. The activity of superoxide dismutase (SOD) and glutathione (GSH) level were decreased. Administration of D in rats pretreated with alpha-tocopherol (alphaT) or acetylsalicylic acid (ASA) decreased the activities of GPx, GR and MDA levels, while the GSH level was increased compared with rats treated with D alone. The SOD activity was increased in rats pretreated with alphaT before D, but decreased on pretreatment with ASA, compared with rats treated with D alone. The results indicated that D induced oxidative stress in rat liver that has been protected by prior administration of alphaT or ASA.     

Chemopreventive potential of luteolin during colon carcinogenesis induced by 1,2-dimethylhydrazine

We investigated the chemopreventive potential of luteolin on hepatic and circulatory lipid peroxidation and antioxidant status during 1,2-dimethylhydrazine induced colon carcinogenesis in rats. Rats were given a weekly subcutaneous injection of DMH at a dose of 20 mg/kg body weight for 15 weeks. Luteolin (0.2 mg/kg body weight/everyday p.o.) was given at the initiation and also at the postinitiation stages of carcinogenesis to DMH treated rats. The animals were sacrificed at the end of 30 weeks. Enhanced lipid peroxidation in the liver and circulation of tumor bearing rats was accompanied by a significant decrease in the levels of plasma and hepatic reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione-S-transferase (GST), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), vitamin C, vitamin E and beta-carotene in DMH treated rats as compared to the control rats. Intragastric administration of luteolin (0.2mg/kg body weight) to DMH-treated rats significantly reduced the incidence and size of tumor in the colon, reduced lipid peroxidation levels and enhanced the plasma and hepatic activities of GSH, GPx, GST, GR, SOD, CAT, vitamin C, vitamin E and beta-carotene. Thus the chemopreventive efficacy of luteolin against colon carcinogenesis is evidenced by our preliminary studies which showed decreased incidence of tumors and the antiperoxidative and antioxidant effect of luteolin. Further study on the exact mechanism of action of luteolin in preventing colon carcinogenesis is yet to be elucidated.     

Antioxidant Enzymatic System in Neuronal and Glial Cells Enriched Fractions of Rat Brain After Aluminum Exposure

The aim of this work was to investigate as to how neurons and glial cells separated from the brain cortex respond to oxidative stress induced by aluminum. Female SD rats were exposed to aluminum at the dose level of 100 mg/kg b.w. for 8 weeks. Neuronal and glial cell-enriched fractions were obtained from rat cerebral cortex by sieving the trypsinated homogenate through a series of nylon meshes, followed by centrifugation on ficoll density gradient. Total glutathione content, glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione-s-transferase (GST) along with antioxidant enzymes superoxide dismutase (SOD), catalase were estimated in neuronal and glial-enriched fractions in both control (N-c and G-c) and aluminum exposed animals (N-a and G-a). Secondary products of lipid peroxidation that is MDA levels were estimated by measuring the (TBARS) levels. Our results indicate that TBARS levels were significantly higher in glial cell fraction of unexposed controls (Gc) than the neuronal cells (Nc). Correspondingly the glial cells had higher levels of GSH, GSSG, GPx and GST where as neurons had higher levels of catalase, SOD and GR. Following aluminum exposures significant increase in the TBARS levels was observed in neurons as compared to glial cells which also showed a significant decrease in SOD and catalase activity. The decrease in the TBARS levels in the glial cells could be related to the increase in the GSH levels, GR activity, and GST activity which were found to be increased in glial enriched fractions following aluminum exposure. The increase in activity of various enzymes viz GR, GST in glial cells as compared to neurons suggests that glial cells are actively involved in glutathione homeostasis. Our conclusion is that glial and neurons isolated from rat cerebral cortex show a varied pattern of important antioxidant enzymes and glial cells are more capable of handling the oxidative stress conditions.     

Temporal variations of lipid peroxidation products, antioxidants and liver marker enzymes in experimental hyperammonemic rats

Circadian variations of lipid peroxidation products: thiobarbituric acid and reactive substances (TBARS), antioxidants: reduced glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and liver marker enzymes such as transaminases (aspartate transaminase (AST) and alanine transaminase (ALT), alkaline phosphatase (ALP) and γ-Glutamyl transpeptidase (GGT) in circulation were analysed in control and ammonium chloride (AC) induced (100 mg/kg bodyweight) hyperammonemic rats. Elevated lipid peroxidation and liver marker enzymes (increased mesor of TBARS, AST, ALT, ALP and GGT) associated with decreased activities of antioxidants (decreased mesor of GPx, GSH, SOD and CAT) were found in hyperammonemic rats. Variations in acrophase, amplitude and r values were also found in between the control and hyperammonemic rats. These alterations clearly indicate that temporal liver marker enzymes and redox status are modulated during hyperammonemic conditions, which may also play a crucial role in disease development.     

Antioxidant activity of costunolide and eremanthin isolated from Costus speciosus (Koen ex. Retz) Sm.

Antioxidant properties of many medicinal plants have been widely recognized and some of them have been commercially exploited. Plant derived antioxidants play a very important role in alleviating problems related to oxidative stress. The present study was aimed at assessing the antioxidant property of costunolide and eremanthin isolated from a medicinal plant Costus speciosus (Koen ex. Retz) Sm. rhizome. Experimental diabetes was induced by a single dose of STZ (60 mg/kg, i.p.) injection. The oxidative stress was measured by tissue thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) content and enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in brain, liver, heart, kidney and pancreas. An increase in TBARS level, a significant reduction in GSH content along with decreased enzymatic activities of SOD, CAT, and GPx were seen in untreated diabetic rats. Administration of either costunolide (20 mg/kg day) or eremanthin (20 mg/kg day) for 60 days caused a significant reduction in TBARS level and a significant increase in GSH content along with increased enzymatic activities of SOD, CAT and GPx in the treated rats when compared to untreated diabetic rats. Acute toxicity test revealed the non-toxic nature of the compounds. The results indicated for the first time the protective effect of costunolide and eremanthin from oxidative stress, thus opening the way for their use in medication.