Effect of nickel chloride on streptozotocin-induced diabetes in rats

The potential of nickel chloride to prevent streptozotocin-induced hyperglycemia was tested in rats in vivo. To induce diabetes, streptozotocin (100 mg/kg body weight) was injected as a single dose. Streptozotocin treatment resulted in a significant decrease in plasma insulin and ceruloplasmin, and pancreatic Cu, protein, and Cu-Zn superoxide dismutase activity. In rats treated with nickel chloride (10 mg/kg body weight) and streptozotocin, these values were comparable with those observed in control rats. The results indicate that nickel chloride injected before streptozotocin prevented streptozotocin-induced hyperglycemia, and suggest that the protective effect was related to Cu-Zn superoxide dismutase activity, mediated by copper.     

Effects of beta-adrenergic blockers with different ancillary properties on lipid peroxidation in hyperthyroid rat cardiac muscle

To determine whether beta-blockade protects rat heart against thyroxine (T4)-induced accelelation of lipid peroxidation, in vivo effects of 3 beta-blockers with different ancillary properties on the mitochondrial oxidative enzyme, antioxidant enzymes and lipid peroxide were investigated. The rats were rendered hyperthyroid by adding T4 to their drinking water for 3 weeks and were treated simultaneously with either carteolol (a blocker with partial agonist activity; 30 mg/kg/day), atenolol (50 mg/kg/day) or arotinolol (a blocker with weak alpha-blocking action; 50 mg/kg/day). The T4-induced tachycardia was alleviated completely by either atenolol or arotinolol, but only partially by carteolol. Cytochrome c oxidase activity in the heart muscle was increased by T4 with a parallel increase in manganese (mitochondrial) superoxide dismutase. Atenolol, but neither carteolol nor arotinolol, suppressed this increase. Similarly, the T4-induced acceleration of lipid peroxidation was suppressed by atenolol alone. Glutathione peroxidase was markedly decreased, and both copper zinc (cytosolic) superoxide dismutase and catalase were also decreased or tended to be decreased by T4. The levels of these 3 enzymes were only minimally affected by the beta-blocker treatments. These results suggest that beta-blockade suppresses mitochondrial hypermetabolism and protects heart muscle against oxidative stress in hyperthyroidism, and that the ancillary properties of beta-blockers such as partial agonist activity and alpha-blocking action negate the protection.     

Involvement of nitric oxide in noradrenaline-induced changes in the activity of antioxidant enzymes and lipid peroxidation in rat brown adipose tissue and heart

The effect of exogenous noradrenaline (NA) (1.6 mg.kg(-1) i.p., 35 min prior sacrifice) on the activity of antioxidant enzymes (AOE) copper zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD) and catalase (CAT), as well as lipid peroxides (LP) concentration were studied in the rat interscapular brown adipose tissue (IBAT) and heart of saline (controls) and N(omega)-nitro-L-arginine methyl ester (L-NAME) treated rats (10 mg.kg(-1), i.p., during 3 days and 20 min before NA). NA differently affects both AOE activities and LP production in the IBAT and heart. Thus, NA inhibited the activity of all IBAT AOE and LP production while in the heart it markedly increased CAT activity only, but had no effect on any of SODs activities and LP concentration. L-NAME, a nitric oxide synthase blocker, completely abolished the NA-induced inhibition of the IBAT AOE and LP production, whereas in the heart it was without effect. In conclusion, these results indicate that both NA and L-NAME effects on AOE activity and LP production are tissue specific and also suggest that nitric oxide mediates the NA-induced inhibition of AOE activity and LP production in the IBAT only.     

Iron-mediated inhibition of mitochondrial manganese uptake mediates mitochondrial dysfunction in a mouse model of hemochromatosis

Previous phenotyping of glucose homeostasis and insulin secretion in a mouse model of hereditary hemochromatosis (Hfe(-/-)) and iron overload suggested mitochondrial dysfunction. Mitochondria from Hfe(-/-) mouse liver exhibited decreased respiratory capacity and increased lipid peroxidation. Although the cytosol contained excess iron, Hfe(-/-) mitochondria contained normal iron but decreased copper, manganese, and zinc, associated with reduced activities of copper-dependent cytochrome c oxidase and manganese-dependent superoxide dismutase (MnSOD). The attenuation in MnSOD activity was due to substantial levels of unmetallated apoprotein. The oxidative damage in Hfe(-/-) mitochondria is due to diminished MnSOD activity, as manganese supplementation of Hfe(-/-) mice led to enhancement of MnSOD activity and suppressed lipid peroxidation. Manganese supplementation also resulted in improved insulin secretion and glucose tolerance associated with increased MnSOD activity and decreased lipid peroxidation in islets. These data suggest a novel mechanism of iron-induced cellular dysfunction, namely altered mitochondrial uptake of other metal ions.     

Effect of an inhibitor of nitric oxide production on Cu−Zn/SOD and its cofactors in diabetic rats

The aim of this study was to investigate the effect of an inhibitor of nitric oxide production, N(omega)-nitro-L-arginine methyl esther (L-NAME) on Cu-Zn/SOD (superoxide dismutase) enzyme activity and copper and zinc concentrations in diabetes-induced rats. The control group consisted of 12 male albino Sprague-Dawley rats, 10-12 wk of age and weighing 300 g. Twenty-six albino Sprague-Dawley rats, 10-12 wk of age and weighing 315 g, constituted the experimental group. The experimental group was divided into two groups. The first group (n=12) constituted streptozotocininduced (55 mg/kg, intraperitoneally) diabetic rats and the second group (n=14) was administered L-NAME (1 mg/kg/d) after streptozotocin induction. For determination of Cu-Zn/SOD activity, spectrophotometry was used. Zinc and copper concentrations were determined by atomic absorption spectrophotometry. Results showed that Cu-Zn/SOD activity was increased significantly in both experimental groups compared to controls, and the increase in the second group was higher than in the first group (p<0.01, p<0.01, p<0.05). Plazma zinc concentration was increased in the second group when compared with controls (p<0.05). Plasma copper was decreased significantly in the second group compared to controls and the first group (p<0.001, p<0.001). Red cell copper concentration was decreased significantly in the first group compared to controls (p<0.05). This study showed that L-NAME administration has ensured an additive effect on the antioxidant defense system, which was proved by the increase in Cu-Zn/SOD activity. This increase might have a protective effect against tissue damage in the acute period, with corresponding changes in zinc and copper concentrations.     

Demonstration of Cu-Zn superoxide dismutase in rat liver peroxisomes. Biochemical and immunochemical evidence.

In this study, by using highly purified rat liver peroxisomes, we provide evidence from analytical cell fractionation, Western blot, and immunocytochemical analysis that Cu-Zn superoxide dismutase is present in animal peroxisomes. Treatment with ciprofibrate, a peroxisome proliferator, increased the peroxisomal superoxide dismutase activity by 3-fold with no effect on mitochondrial activity but a marked decrease in cytosolic superoxide dismutase activity, further supporting that besides cytosolic and mitochondrial localization, Cu-Zn superoxide dismutase is present in peroxisomes also. Demonstration of superoxide dismutase in peroxisomes suggests a new role for this organelle in pathophysiological conditions, such as ischemia-reperfusion injury.     

Inhibitory effects of a manganese superoxide dismutase isolated from garlic (Allium sativum L.) on in vitro tumoral cell growth

Reactive oxygen species are implicated in cancer development and antioxidants in general and superoxide dismutases and superoxide dismutase mimetic in particular, and they inhibit malignant transformation. We examinate the effects of an isolated manganese superoxide dismutase from a medicinal plant Allium sativum. The protein was prepared by a serial of chromatographic techniques: gel filtration and diethylaminoethyl ions exchanger. The enzyme has a specific activity equal to 55 U/mg. Two tumoral cell lines, porcine endothelial cells and mouse melanoma cells were exposed to garlic superoxide dismutase. The exogenous manganese superoxide dismutase is able to modify the intracellular level of reactive oxygen species by eliminating superoxide anion and producing hydrogen peroxide. The cell viability of the two lines was not significantly affected but the cell multiplication was arrested. This effect obtained in the presence of manganese superoxide dismutase correlates with the activation and modulation of phospho‐extracellular signal‐regulated kinases proteins, implicated in the control of several biological processes including cell proliferation. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009     

Glucose suppresses superoxide generation in metabolically responsive pancreatic beta cells

High rates of glucose metabolism and mitochondrial electron transport have been associated with increased mitochondrial production of reactive oxygen species (ROS). This mechanism was also proposed as a possible cause for dysfunction and death of pancreatic beta cells exposed to high glucose levels. We examined whether high rates of glucose metabolism increase ROS production in purified rat beta cells. Glucose up to 20 mm did not stimulate H(2)O(2) or superoxide production, whereas it dose-dependently increased cellular NAD(P)H and FADH(2) levels with an EC(50) around 8 mm. On the contrary, glucose concentration-dependently suppressed H(2)O(2) and superoxide formation, with a major effect between 0 and 5 mm, parallel to an increase in cellular NAD(P)H levels. This suppressive effect was more marked in beta cells with higher NAD(P)H responsiveness to glucose; it was not observed in glucagon-containing alpha cells, which lacked a glucose-induced increase in NAD(P)H. Suppression was also induced by the mitochondrial substrates leucine and succinate. Experiments with electron transport chain inhibitors indicate a role of respiratory complex I in ROS production at low mitochondrial activity and low NADH levels. Superoxide production at low glucose is potentially cytotoxic, because scavenging by the superoxide dismutase mimetic agent manganese(III)tetrakis(4-benzoic acid)porphyrin was found to reduce the rate of beta cell apoptosis. Analysis of islets cultured at 20 mm glucose confirmed that this condition does not induce ROS production in beta cells as a result of their increased rates of glucose metabolism. Our study indicates the need of beta cells for basal nutrients maintaining mitochondrial NADH production at levels that suppress ROS accumulation from an inadequate respiratory complex I activity and thus inhibit a potential apoptotic pathway.     

Manganese superoxide dismutase from a higher plant

A manganese-containing superoxide dismutase (EC 1.15.1.1) was purified to homogeneity from a higher plant for the first time. The enzyme was isolated fromPisum sativum leaf extracts by thermal fractionation, ammonium sulfate salting out, ion-exchange and gel-filtration column chromatography, and preparative polyacrylamide gel electrophoresis. Pure manganese superoxide dismutase had a specific activity of about 3,000 U mg^-1 and was purified 215-fold, with a yield of 1.2 mg enzyme per kg whole leaf. The manganese superoxide dismutase had a molecular weight of 94,000 and contained one g-atom of Mn per mol of enzyme. No iron and copper were detected. Activity reconstitution experiments with the pure enzyme ruled out the possibility of a manganese loss during the purification procedure. The stability of manganese superoxide dismutase at-20°C, 4°C, 25°C, 50°C, and 60°C was studied, and the enzyme was found more labile at high temperatures than bacterial manganese superoxide dismutases and iron superoxide dismutases from an algal and bacterial origin.Abbreviations NBT nitro blue tetrazolium - SOD superoxide dismutase (EC 1.15.1.1)     

Increase in manganese superoxide dismutase activity in the mouse heart after X-irradiation

Local X-irradiation of mouse heart caused a large increase in manganese superoxide dismutase activity (MnSOD) in this organ but not in copper and zinc containing superoxide dismutase (CuZn SOD) activity. MnSOD induction was both dose and time dependent. Another mitochondrial enzyme, citrate synthase, was not induced by X-irradiation. The amount of immunoreactive MnSOD also increased after X-irradiation, showing that the amount of MnSOD protein increased after X-irradiation. The response to X-irradiation was found to be biphasic—with one large peak and one smaller peak of manganese superoxide dismutase activity. The effect of various inhibitors of cellular activities on these two peaks of MnSOD activity was examined. Cycloheximide, a cytosolic protein synthesis inhibitor, abolished both peaks of MnSOD activity, while chloramphenicol, a mitochondrial protein synthesis inhibitor, has no effect on either peak. Actinomycin D, a RNA-synthesis inhibitor, lowered both peaks, but had more of an effect on the second peak than on the first. In vivo protein synthesis studies using [³H]arginine showed that an increase in new protein synthesis occurred during the time period of the second peak, but did not occur during the first peak. These results are consistent with the hypothesis that MnSOD induction occurs in two peaks with the first peak due to a preformed MnSOD protein or mRNA for MnSOD and the second peak due to an increase in new protein synthesis.     

The amino-acid sequence of rabbit Cu-Zn superoxide dismutase

The primary structure of Cu-Zn superoxide dismutase from rabbit liver was investigated. The reduced and S-carboxymethylated enzyme was treated with cyanogen bromide, trypsin or Staphylococcus aureus proteinase V8. The resulting peptides were separated by high-performance liquid chromatography and sequenced by automated Edman degradation. With the exception of the N- and C-terminus the complete sequence was established by means of overlapping peptides. The N-terminus is blocked and thus not susceptible to Edman degradation. The amino-acid composition of the tryptic N-terminal peptide corresponds to that of the cytoplasmatic Cu-Zn superoxide dismutases of other mammals investigated. The chromatographic behaviour of these N-terminal peptides on a reversed phase C18 column is also identical, thus suggesting also for the rabbit Cu-Zn superoxide dismutase the N-terminal sequence Ac-Ala-Thr-Lys. The C-terminus was demonstrated to have the sequence -Ile-Ala-Pro by enzymatic degradation with carboxypeptidase Y. The complete amino-acid sequence of the rabbit Cu-Zn superoxide dismutase consists of 152 amino-acids and shows the expected homology to other Cu-Zn enzymes published so far. The aspartate and six histidine residues known to complex the metal ions are conserved at homologous positions. This also applies for the arginine residue near the C-terminus which is supposed to direct the anionic superoxide radical towards the active centre of the enzyme. The amino acid sequence of the rabbit Cu-Zn superoxide dismutase corresponds to those of other mammals in more than 80% of its amino-acid residues. From a total of 152 amino-acid residues the rabbit shares with rat 128, with mouse 130, with horse 127, with pig 126/127, with cattle 130 and with man 131 amino acids in homologous positions. However the Cu-Zn superoxide dismutases of closely related mammals like rats and mice differ in only five amino acid residues of their sequence. A phylogenetic closer relatedness between lagomorphs and rodents than between other orders of mammals, could not be derived from the sequence data given. Rather rodents and lagomorphs are to be considered as two evolutionary independent orders of mammals.     

Superoxide dismutase during glucose repression of Hansenula polymorpha CBS 4732

Hansenula polymorpha CBS 4732 was studied during cultivation on methanol and different glucose concentrations. Activities of Cu/Zn and Mn superoxide dismutase, catalase and methanol oxidase were investigated. During cultivation on methanol, increased superoxide dismutase and catalase activities and an induced methanol oxidase were achieved. Transfer of a methanol grown culture to medium with a high glucose concentration caused growth inhibition, low consumption of carbon, nitrogen and phosphate substrates, methanol oxidase inactivation as well as decrease of catalase activity (21.8 +/- 0.61 deltaE240 x min(-1) x mg protein(-1)). At the same time, a high value for superoxide dismutase enzyme was found (42.9 +/- 0.98 U x mg protein(-1), 25% of which was represented by Mn superoxide dismutase and 75% - by the Cu/Zn type). During derepression methanol oxidase was negligible (0.005 +/- 0.0001 U x mg protein(-1)), catalase tended to be the same as in the repressed culture, while superoxide dismutase activity increased considerably (63.67 +/- 1.72 U x mg protein(-1), 69% belonging to the Cu/Zn containing enzyme). Apparently, the cycle of growth inhibition and reactivation of Hansenula polymorpha CBS 4732 cells is strongly connected with the activity of the enzyme superoxide dismutase.     

An Estimation of the Manganese Requirement for Broilers from 1 to 21 Days of Age

A dose–response experiment was conducted to find the sensitive and consistent biomarker for the estimation of dietary manganese (Mn) requirement and establish the optimal Mn level for broilers fed a practical corn–soybean meal diet from 1 to 21 days of age post-hatching. A total of 480 1-day-old Arbor Acres male chicks were randomly allotted to one of eight treatments with five replicates of 12 birds each and fed diets supplemented with 0, 20, 40, 60, 80, 100, 120, or 140 mg Mn/kg from reagent grade Mn sulfate. Tissue Mn concentrations, manganese-containing superoxide dismutase (MnSOD) activity, and MnSOD mRNA concentration within heart tissue were analyzed at 7, 14, and 21 days of age. Tissue Mn concentrations and heart MnSOD activity showed significant quadratic responses, and heart MnSOD mRNA concentration showed an asymptotic response to dietary supplemental Mn level, respectively. The estimate of dietary Mn for chicks from 1 to 21 days of age was 122–128 for heart Mn concentration, 141–159 for pancreas Mn concentration, 127–138 for liver Mn concentration, and 135–156 mg/kg for heart MnSOD activity, respectively. Heart MnSOD mRNA concentration was a consistent index for the estimation of the Mn requirement of broilers. Based on this index, the estimate of dietary Mn requirement for broilers from 1 to 21 days of age post-hatching was about 130 mg/kg, which was a little more than two times of the current NRC (1994) requirement.     

Relative Bioavailability of Manganese Proteinate for Broilers Fed a Conventional Corn–Soybean Meal Diet

An experiment was conducted to investigate the bioavailability of organic manganese proteinate (Mn) relative to inorganic Mn sulfate for broilers fed a conventional corn–soybean meal basal diet. A total of 448-day-old Arbor Acres commercial male chicks were fed the Mn-unsupplemented basal diet (control) or basal diet supplemented with 60, 120, or 180 mg Mn/kg from each Mn source. At 21 days of age, heart tissue was excised for testing DM, Mn concentration, manganese superoxide dismutase (MnSOD) activity, and MnSOD mRNA level. The Mn concentration, MnSOD activity, and MnSOD mRNA level in heart tissue increased (P < 0.01) linearly as dietary manganese concentration increased. Based on slope ratios from multiple linear regressions of the above three indices on added Mn level, there was no significant difference (P > 0.21) in bioavailability between Mn proteinate and Mn sulfate for broilers in this experiment.     

Serotonin-type 3 receptors mediate intestinal Polycose- and glucose-induced suppression of intake

Ondansetron, a selective serotonin-type 3 (5-HT(3)) receptor antagonist, was used to test the hypothesis that duodenal infusion of isosmotic solutions of Polycose or its hydrolytic product glucose suppressed intake through 5-HT(3) receptors. Polycose suppressed sucrose intake across both concentrations infused (132 mM, 7.6 +/- 0.6 ml; 263 mM, 2.3 +/- 0.5 ml), compared with intake under control conditions (12.6 +/- 0.3 ml, P <0.001). Pretreatment with 1.0 mg/kg ondansetron attenuated reduction of sucrose intake induced only by the highest concentration of Polycose (4.6 +/- 0.8 ml, P = 0.004). Dose-response testing revealed that suppression of food intake by 263 mM Polycose was equally attenuated by ondansetron administered at 1.0, 2.0, and 5.0 mg/kg but not when given at 0.125, 0.25, and 0.5 mg/kg. Acarbose, an alpha-glucosidase inhibitor, attenuated Polycose-induced suppression of food intake, and pretreatment with 1.0 mg/kg ondansetron had no further effect. Suppression of intake after 990 mM glucose but not mannitol infusion was attenuated by pretreatment with 1.0 mg/kg ondansetron. The competitive SGLT(1) inhibitor, phloridzin, had no effect on 60-min 990 mM glucose-induced suppression of intake or the ability of ondansetron to attenuate this suppression of intake. Conversely, glucose-induced suppression of intake was attenuated by phloridzin at earlier time points and further attenuated when rats were pretreated with 1.0 mg/kg ondansetron. Ondansetron administration alone had no effect on intake at any dose tested. We conclude that 5-HT(3) receptors participate in the inhibition of food intake by intraduodenal infusion of carbohydrate solutions through a posthydrolytic, preabsorptive mechanism.     

Superoxide dismutase in mouse brain, liver and heart in the presence and absence of dietary vitamin E1

Three groups of weanling mice, 8 to a group, were fed three different diets for a 12-month period. The first group was fed a basal diet deficient in vitamin E, the second group was fed the basal diet plus 30 mg/kg diet d-alpha-tocopheryl acetate and the third group, the basal diet plus 300 mg/kg diet d-alpha-tocopheryl acetate. After 12 months, superoxide dismutase activity was measured in the liver, brain and heart. The enzyme activity in the liver was found to be 10 times the activity in either the brain or the heart. Dietary alpha-tocopherol did not influence superoxide dismutase activity in any of the tissues studied.     

大革耳子实体多糖抗氧化活性

作者对大革耳子实体多糖的抗氧化能力及单糖组分进行了分析,并探究了大革耳子实体多糖体外对羟自由基、超氧阴离子自由基、1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基、2'-联氨-双-3-乙基苯并噻唑啉-6-磺酸[2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid),ABTS]自由基的清除能力和铁离子还原能力;以人正常肝细胞系LO2为材料建立了过氧化氢细胞氧化损伤模型,并探讨大革耳子实体多糖在细胞水平的抗氧化能力;通过苯酚硫酸法及HPLC检测了子实体多糖的单糖含量及组分。体外化学抗氧化实验结果显示,大革耳子实体多糖对羟自由基、超氧阴离子、DPPH自由基和ABTS自由基的清除能力较强,且具有较高的铁离子还原能力;细胞水平抗氧化实验表明,大革耳子实体多糖对人正常肝细胞系LO2的H₂O₂氧化损伤具有显著的保护作用,并能极显著提高受损细胞内过氧化氢酶（catalase,CAT）（P<0.01）及超氧化物歧化酶（superoxide dismutase,SOD）（P<0.01）的活力。大革耳子实体活性多糖主要单糖含量及组分依次为：葡萄糖（2 985.50mg/kg）、甘露糖（1 867.23mg/kg）、木糖（814.98mg/kg）、半乳糖（724.24mg/kg）、岩藻糖（443.72mg/kg）、葡萄糖醛酸（419.41mg/kg）、鼠李糖（81.18mg/kg）、阿拉伯糖（64.40mg/kg）、核糖（39.95mg/kg）、半乳糖醛酸（24.40mg/kg）。本研究结果为更好的推广应用和科学开发大革耳提供了基础资料。     

Apparent superoxide dismutase-like activity of immunoglobulin

Summary

Using various superoxide generating systems and nitroblue tetrazolium or cytochrome c as superoxide detector molecules it is possible to assess the superoxide dismutase activity of proteins. Intact antibodies raised to different antigens, the Fab’ fragment of anti-TNF [M632] and well-characterized recombinant Fv fragments of the murine antibody NQ11.7.22 appear to possess superoxide dismutase (SOD)-like activity.

Kinetic characteristics of the SOD-like activity of NQ11.7.22-Fv fragments suggest an enzymatic property and these fragments behave in an analogous manner to human erythrocyte Cu-Zn SOD. Furthermore, the SOD-like activity of the NQ11.7.22-Fv fragment is affected by certain single-point mutations in the amino acid composition and has a pH optimum of 6.2–6.6 which is unlike Cu-Zn SOD (pH 7.8–8.2). A change in tyrosine at the 32 position in the heavy chain and histidine at position 27 of the light chain of the NQ11.7.22-Fv fragment results in a profound reduction in SOD-like activity. Tyrosine at the 32 position in the heavy chain is known to play a significant role in antigen binding suggesting that the SOD-like activity occurs at the antigen-binding site itself. Single-point mutations at the periphery of the antigen combining site on the NQ11.7.22-Fv fragment had little or no effect on SOD-like activity.

Further studies show that immunoglobin (lgG-1), a commercially available murine monoclonal antibody, can also enhance the generation of hydrogen peroxide, the product of superoxide dismutation, when present in superoxide producing systems. The generation of hydrogen peroxide was increased by low pH (pH 6.25) with lgG-1 but reduced with Cu-Zn SOD.     

Prevention of kainic acid-induced changes in nitric oxide level and neuronal cell damage in the rat hippocampus by manganese complexes of curcumin and diacetylcurcumin

Curcumin is a natural antioxidant isolated from the medicinal plant Curcuma longa Linn. We previously reported that manganese complexes of curcumin (Cp-Mn) and diacetylcurcumin (DiAc-Cp-Mn) exhibited potent superoxide dismutase (SOD)-like activity in an in vitro assay. Nitric oxide (NO) is a free radial playing a multifaceted role in the brain and its excessive production is known to induce neurotoxicity. Here, we examined the in vivo effect of Cp-Mn and DiAc-Cp-Mn on NO levels enhanced by kainic acid (KA) and L-arginine (L-Arg) in the hippocampi of awake rats using a microdialysis technique. Injection of KA (10 mg/kg, i.p.) and L-Arg (1000 mg/kg, i.p.) significantly increased the concentration of NO and Cp-Mn and DiAc-Cp-Mn (50 mg/kg, i.p.) significantly reversed the effects of KA and L-Arg without affecting the basal NO concentration. Following KA-induced seizures, severe neuronal cell damage was observed in the CA1 and CA3 subfields of hippocampal 3 days after KA administration. Pretreatment with Cp-Mn and DiAc-Cp-Mn (50 mg/kg, i.p.) significantly attenuated KA-induced neuronal cell death in both CA1 and CA3 regions of rat hippocampus compared with vehicle control, and Cp-Mn and DiAc-Cp-Mn showed more potent neuroprotective effect than their parent compounds, curcumin and diacetylcurcumin. These results suggest that Cp-Mn and DiAc-Cp-Mn protect against KA-induced neuronal cell death by suppression of KA-induced increase in NO levels probably by their NO scavenging activity and antioxidative activity. Cp-Mn and DiAc-Cp-Mn have an advantage to be neuroprotective agents in the treatment of acute brain pathologies associated with NO-induced neurotoxicity and oxidative stress-induced neuronal damage such as epilepsy, stroke and traumatic brain injury.