Rat Liver Catalase Research Articles

Supplementation of cumin seed powder prevents oxidative stress, hyperlipidemia and non-alcoholic fatty liver in high fat diet fed rats

The present investigation was an attempt to evaluate the hypoglycemic, lipid-lowering, antioxidant and hepatoprotective effects of cumin (Cuminum cyminum family: Apiaceae) supplementation in high fat (HF) diet fed rats. Male Wistar rats were divided into four groups, such as control, control+ cumin, HF and HF+ cumin. Oral glucose tolerance test, plasma lipids, oxidative stress parameters, antioxidant enzymes activities, and liver dysfunction marker enzyme activities were evaluated. Additionally, histological staining of liver tissue was performed to evaluate the inflammatory cells infiltration, iron deposition and fibrosis. The current investigation demonstrated that 1% (w/w) supplementation of cumin powder significantly reduced HF diet-induced glucose intolerance, epididymal and mesenteric fat wet weights and lipid parameters like triglycerides, total cholesterol and low-density lipoproteins. Oxidative stress-related biomarkers including thiobarbituric acid reactive substances (TBARS), nitric oxide (NO) and advanced oxidation protein product (APOP) were also reduced by cumin supplementation. Moreover, HF-diet increased the activity of hepatic biomarker enzymes such as alanine transaminase (ALT) and alkaline phosphatase (ALP) activities which were significantly reduced by cumin powder supplementation. On the other hand, cumin powder supplementation was able to restore the reduced glutathione level with parallel augmentation of the antioxidant enzymes activities such as superoxide dismutase (SOD) and catalase in liver of HF diet-fed rats. Additionally, histological assessments confirmed that cumin powder supplementation also normalized the fat droplet deposition and inflammatory cells infiltration in the liver of HF diet-fed rats. This study suggests that cumin powder supplementation ameliorates dyslipidemia, oxidative stress and hepatic damage in HF diet-fed rats.

Diabetic complications and oxidative stress: The role of phenolic‐rich extracts of saw palmetto and date palm seeds

Recently, we reported that the date palm seed (DP) and saw palmetto seed (SP) extracts possessed a great amount of phenolic contents with potent antioxidant, antimicrobial, and anti-inflammatory activities. Therefore, this study aimed to assess the role of DP and SP phenolic-rich extracts in modulating diabetic complications and oxidative stress in the STZ- diabetic rat. DP and SP extracts significantly inhibited both microbial and pancreatic α-amylases. The STZ-induced diabetic rat groups treated with DP and SP extracts exhibited reversed hyperglycemia (40% and 54%, p<.001-.01) and body weight (70%, p<.001) alteration close to normal. Moreover, DP and SP extracts modulated serious damages in the structures of the pancreas, kidney, and liver of diabetic rats. DP and SP extracts improved the decline of the activities of antioxidant enzymes: Catalase, glutathione-S-transferase, glutathione reductase, and glutathione peroxidase in liver, kidney, and pancreas of the diabetic rats. PRACTICAL APPLICATIONS: Generally, date seed is a rich source of dietary fibers, polyphenols, and antioxidants and used in foods and pharmaceuticals. Our study reported that date palm seed (DP) and saw palmetto seed (SP) phenolic-rich extracts attenuated diabetes and its complications, probably tissue regeneration and normalizing the oxidative stress in the STZ-induced diabetic rat.

In vitro and in vivo Antioxidant Properties of Extracts from the Root of Curcuma longa Linn

Many plants possess antioxidants that exhibit additive or synergistic activities. The antioxidant activities of the root of Curcuma longa Linn extracts extracted different solvents were investigated by using several established in vitro systems: α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity, hydrogen Peroxide scavenging activity (HPSA), nitric oxide radical scavenging activity (NOSA) and ferric reducing antioxidant power (FRAP). The result showed that methanol extract exhibited greater antioxidant activity in vitro which was statistically significant compared to the other extracts. Based on the in vitro results, the methanol extract was subjected to column chromatography. Six pooled fractions (FI-FVI) were evaluated for in vivo antioxidant activity in liver and kidney of alloxan-induced diabetic rats using a total of forty-five (45) rats which were grouped into nine (9) groups of five (5) rats. The in vivo antioxidants showed a significant decrease in superoxide dismutase (SOD), catalase (CAT) and gluthatione peroxidase (GPx) levels in both liver and kidney of Alloxan-induced diabetic rats. These changes were significantly reversed after treatment with methanol fraction II and the standard drug. Thus, Curcuma longa Linn may be useful in the management of diabetes and oxidative stress.

Role of zinc on lipid peroxidation and antioxidant status in liver and muscle tissues of rats under ammonium sulfate-induced stress

Background: Ammonia is an important source of nitrogen metabolism and it is necessary for the synthesis of protein and amino acids. An excessive level of ammonia leads to disturbing the physiological functions of the body, causes to increase the free radical levels in tissues and body fluids, its reveal that damage of tissue by reactive oxygen species (ROS) changes of acid-base lances in the body fluid’s causes’ physiological disturbance and damage of organs. Aims and Objectives: The present study was conducted to assess the mitigating role of zinc on ammonium sulfate (AS)-induced biochemical alterations (lipid peroxidation [LPO] and antioxidants) in rat liver and muscle. Materials and Methods: Rats were divided into four groups (six animals in each group). Group I (GI) served as control and rats provided with normal diet and water, Group II (AS) rats treated intraperitoneal (i.p) with 18.3 mg/kg b.w of AS, Group III (zinc chloride [Zc]) rats administered with Zc (4 mg/kg b.w i.p), and Group IV (AS + Zc) treated with both of AS (18.3 mg/kg bwi.p) plus Zc (4 mg/kg b.w i.p) Zc given after 1 h dosage of AS. Results: In the present investigation, AS-treated animals showed a significant increase in the levels of LPO and declined levels of selected antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) levels in the liver and muscle of rats. On the other hand, only zinc-treated rats (Zc) showed no significant variations in LPO and antioxidants in the liver and muscle. However, in AS + Zc treated animals, elevated levels of LPO and decreased SOD, CAT, GPx, and GR antioxidant levels were reversed to normal when compared with AS-treated rats. Conclusion: Accordingly, these findings suggest that zinc supplementation significantly inhibits the oxidative stress in hepatic cells and muscle cells in AS toxicity.

Effect of Extract and Ellagic Acid from Geranium schiedeanum on the Antioxidant Defense System in An Induced-Necrosis Model.

Geranium schiedeanum has been used in traditional therapies as an antiseptic, antipyretic, and as analgesic. The present study was designed to evaluate the pretreatment with G. schiedeanum total extract (GS) and its active metabolites on stimulating the endogenous antioxidant defense system (EADS): catalase (Cat), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione reduction index (RI GSH/GSSG) in rat liver treated with a sublethal dose (6.6 mmol/Kg) of thioacetamide (TAA) in order to probe the capacity of GS and the active compounds to reduce liver injury. This was assessed by measuring aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin (BILT) in rats pretreated or not with TAA, and pretreated or not with GS and its metabolites. The results showed that GS was able to induce the production of EADS enzymes, increasing redox index GSH/GSSG at 24 and 48 h after intoxication, and both the extract and the ellagic acid exhibited a significant reduction of hepatic damage markers. Our data confirmed the hepatoprotective effect of GS and its metabolites, like ellagic acid, support the possible use of this extract in the treatment of liver injury.

In Vitro and In Vivo Antioxidant and Anti-Hyperglycemic Activities of Moroccan Oat Cultivars.

Improvement of oat lines via introgression is an important process for food biochemical functionality. This work aims to evaluate the protective effect of phenolic compounds from hybrid Oat line (F11-5) and its parent (Amlal) on hyperglycemia-induced oxidative stress and to establish the possible mechanisms of antidiabetic activity by digestive enzyme inhibition. Eight phenolic acids were quantified in our samples including ferulic, p-hydroxybenzoic, caffeic, salicylic, syringic, sinapic, p-coumaric and chlorogenic acids. The Oat extract (2000 mg/kg) ameliorated the glucose tolerance, decreased Fasting Blood Glucose (FBG) and oxidative stress markers, including Superoxide dismutase (SOD), Catalase (CAT), Glutathione peroxidase (GPx), Glutathione (GSH) and Malondialdehyde (MDA) in rat liver and kidney. Furthermore, Metformin and Oat intake prevented anxiety, hypercholesterolemia and atherosclerosis in diabetic rats. In vivo anti-hyperglycemic effect of Oat extracts has been confirmed by their inhibitory activities on α-amylase (723.91 μg/mL and 1027.14 μg/mL) and α-glucosidase (1548.12 μg/mL & 1803.52 μg/mL) enzymes by mean of a mixed inhibition.

Influence of Melatonin-Correcting Drugs (Melaxen and Valdoxan) on the Levels of Superoxide Dismutase and Catalase Gene Transcription in Rats with Experimental Hyperthyroidism

The influence of the melatonin-correcting drugs melaxen and Valdoxan on the gene-transcription level of superoxide dismutase (SOD, EC 1.15.1.1) and catalase (EC 1.11.1.6) in liver and heart of rats with hyperthyroidism has been investigated. Administration of these drugs to rats with model pathology leads to changes in SOD and catalase expression in their tissues toward the control values.

Relationships between Mechanical Nociceptive Threshold and Activity of Antioxidant Enzymes in Male Rats with Experimental Type I Diabetes Mellitus.

We analyzed the dynamics of neuropathic pain development and changes in catalase and superoxide dismutase (SOD) activities in the brain, liver, and skeletal muscles of male Wistar rats with 1-month streptozotocin-induced diabetes mellitus. A decrease in mechanical nociceptive threshold was revealed that progressed during the disease progress. Insulin treatment restored nociceptive threshold in diabetic animals to the control values. Catalase activity in the liver and skeletal muscles of diabetic rats increased by 1.5 and 2 times, respectively, in comparison with the control, while insulin treatment reduced enzyme activity to the control level. In the brain, catalase activity was reduced by 1.5 times and insulin therapy did affect this parameter. SOD activity in the studied tissues remained unchanged during diabetes and was not affected by insulin therapy. A strong negative correlation between nociceptive threshold in rats and catalase activity in their liver and skeletal muscles was found.

Влияние мелаксена и вальдоксана на уровень транскриптов супероксиддисмутазы и каталазы при экспериментальном гипертиреозе у крыс

Исследовано воздействие мелаксена и вальдоксана на уровень транскриптов генов супероксиддисмутазы (СОД (КФ 1.11.1.6)) и каталазы (КФ 1.11.1.6) в печени и сердце крыс с гипертиреозом. Установлено, что введение данных препаратов при этой патологии сопровождается изменением экспрессии СОД и каталазы в исследуемых тканях крыс в сторону контрольных значений.

Antioxidant and hepatoprotective effects of fermented red ginseng against high fat diet-induced hyperlipidemia in rats.

This study was performed to investigate the antioxidant and hepatoprotective effects of fermented red ginseng (Panax ginseng C.A. Meyer; FRG) on high-fat diet-induced hyperlipidemia in rats. Sprague-Dawley rats were divided into four groups of seven: normal control, NC; high-fat diet control, HFC; high-fat diet–0.5% FRG, HF-FRGL; and high-fat diet–1% FRG, HF-FRGH. All rats were fed a high-fat diet for eight weeks, except those in the NC group, while rats in the FRG treatment groups received drinking water containing 0.5% or 1% FRG. After eight weeks of treatment, levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), triglycerides (TG), low-density lipoprotein-cholesterol (LDL-C), and high-density lipoprotein-cholesterol (HDL-C) in the serum were measured. The concentration of the oxidative stress marker malondialdehyde (MDA), and activity of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in rat liver were evaluated. Histological analysis of the liver was performed using hematoxylin and eosin. The high-fat diet markedly increased serum levels of ALT, AST, TC, TG, and LDL-C and hepatic MDA levels, while administration of FRG to the hyperlipidemic rats resulted in a significant decline in the levels of these parameters. Furthermore, the decline in the levels of serum HDL-C and hepatic SOD, CAT, and GSH-Px induced by the high-fat diet was attenuated by FRG treatment. In addition, histopathological analysis of liver sections suggested that FRG treatment also provided protection against liver damage. These results suggested that FRG improved lipid profiles, inhibited lipid peroxidation, and played a protective role against liver injury in hyperlipidemic rats.

Differential in vitro effects of homoarginine on oxidative stress in plasma, erythrocytes, kidney and liver of rats in the absence and in the presence α-tocopherol, ascorbic acid or L-NAME.

In the present study, we evaluated the in vitro effects of homoarginine (hArg) at 1, 10 and 20 µM on thiobarbituric acid-reactive substances (TBA-RS), total sulfhydryl content and on the activity of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in plasma, erythrocytes, kidney and liver of rats (60 days old). We also investigated the influence of the antioxidants (each at 1 mM) α-tocopherol and ascorbic acid, as well as of the nitric oxide synthase inhibitor N (G)-nitro-L-arginine methyl ester (L-NAME) at 1 mM, on the effects elicited by hArg on the parameters tested. In plasma, hArg at concentrations of 10 and 20 μM decreased moderately the total sulfhydryl content. At 20 µM, hArg enhanced moderately TBA-RS in the plasma. In plasma, the effects of hArg (20 µM) on TBA-RS and total thiol content were abolished by α-tocopherol, ascorbic acid and L-NAME. At all concentrations tested, hArg did not exert any effect on CAT, SOD or GSH-Px activity in the erythrocytes. In the kidney, hArg exerted effects only at 20 µM and in a different manner: TBA-RS levels increased and total thiol content and CAT activity decreased, while SOD and GSH-Px activity increased. In the renal medulla, α-tocopherol and ascorbic acid but not L-NAME abolished the effects of hArg (20 µM) on TBA-RS, while all agents inhibited the hArg-induced increase in SOD activity. In the renal cortex, α-tocopherol, ascorbic acid and L-NAME abolished the effects of hArg (20 µM) on the total sulfhydryl content and GSH-Px activity, but L-NAME did not reverse the inhibitory effects of hArg on CAT activity. In the liver, no effects of hArg were observed of all biomarkers measured. At the pathologically high concentration of 20 µM, as it may occur in plasma in hyperargininemia, hArg may enhance lipid peroxidation and thiol oxidation and inhibit CAT activity, but may increase SOD and GSH-Px activity predominantly in the kidney.

Electrophilic and Reactive Oxygen Species Detoxification Potentials of Chalcone Dimers is Mediated by Redox Transcription Factor Nrf‐2

Nuclear erythroid related factor-2 (Nrf2), a redox-transcription factor, plays a critical role in the detoxification of electrophilic and reactive oxygen species that halt various biochemical and molecular processes. This makes it a candidate for regulation by polyphenols. This study investigates the capability of chalcone dimers (lophirones B and C) to induce expressions and activities of cytoprotective enzymes. Chalcone dimers administration to rats not only induced the Nrf2, but also suppressed cytoplasmic Kelch-like ECH-associated protein 1 (Keap1) expressions. In addition, the chalcone dimers significantly (p < 0.05) increased the expressions and activities of nicotinamide adenine dinucleotide and reduced quinone oxidoreductase-1, glutathione-S-transferase, epoxide hydrolase and uridyl glucuronosyl transferase in rat liver. Also, activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase in rat liver increased significantly (p < 0.05). Overall, lophirones B and C increased the expressions and activities of cytoprotective proteins in rat liver possibly through the reduction of cytoplasmic Keap1 expression, leading to the nuclear translocation of Nrf2.

Caffeic acid protects tissue antioxidants and DNA content in methamphetamine induced tissue toxicity in Sprague Dawley rats

Caffeic acid (CA) (3,4-dihydroxycinnamic acid) is among the major hydroxycinnamic acids. Hydroxycinnamic acid is the major subgroup of phenolic compounds. Methamphetamine (METH) is a potent addictive psychostimulant. Chronic use and acute METH intoxication can cause substantial medical consequences, including spleen, kidney, liver and heart. The objective of the present study was to evaluate the antioxidant activity of CA to protect against oxidative stress and DNA damage to various organs in METH toxicity. Thirty-two male Sprague Dawley (SD) rats were divided into four equal groups: group 1 was injected (i.p) with saline (1 mL/kg) while groups 2,3 and 4 were injected (i.p) with METH (10 mg/kg) twice a day over five days period. Where 100 & 200 mg/kg of CA were injected (i.p) into groups 3 and 4, respectively one day before exposure to METH injections. Tissue antioxidants and DNA content were evaluated in different tissues. METH decreased glutathione (GSH) and glutathione peroxidase (GPx) levels while increased malondialdehyde (MDA), catalase (CAT) and protein carbonyl levels in brain (hypothalamus), liver, and kidney tissues of rats. METH increased hyperdiploidy in these tissues and DNA damage results. Prior treatment of CA to animals exposed to METH restores the above parameters to the normal levels and preserves the DNA content of these tissues. These results were supported by histopathological investigations. In conclusion, METH induced oxidative stress and DNA damage and pretreatment of CA before METH injections prevented tissue oxidative stress and DNA damage in METH-treated animals.

Lipid Profile and Antioxidant Enzymes in Normal and Stressed Rat Fed with Palm Olein

Problem statement: The objective of the study was to evaluate the effect of Red Palm Olein (RPO) and Palm Olein (PO) on lipid profile and antioxidant enzyme in normal and stressed rat. Approach: Thirty six Sprague Dawley male rats which were randomly divided into six groups of 6 rats per group (tree normal groups and three stressed groups) were treated with 15% of RPO and PO for four weeks. Results: The results at 4 weeks of treatment showed a decline in Low Density Lipoprotein Cholesterol (LDL-C) level at RPO and PO for normal and stressed groups compared to the control group. The High Density Lipoprotein Cholesterol (HDL-C) level increased in RPO and PO of the normal and stressed groups. There was significant decreased (p?0.05) in the TC in RPO normal group for 4 weeks of treatment compared to the control group while the TC in PO was within the normal range and increased in stressed group. After 4 weeks of treatment the study indicated that there was no significant (p?0.05) effect on antioxidant enzyme (superoxide dismutase) in stressed rat liver but there was a significant decreased (p?0.05) on catalase in stressed rat liver. Conclusion: These results could be due to the high content of vitamin E (tocopherols and tocotrienols) and ?-carotene in red palm olein.

Effect of Four Different Vegetable Oils (Red Palm Olein, Palm Olein, Corn Oil, Coconut Oil) on Antioxidant Enzymes Activity of Rat Liver

The objective of the study was to evaluate the effect of four different vegetable oils [red palm olein (RPO), palm olein (PO), corn oil (CO), coconut oil (COC)] on antioxidant enzymes activity of rat liver. Sixty six Sprague Dawley male rats which were randomly divided into eleven groups of 6 rats per group and were treated with 15% of RPO, PO, CO and COC for 4 and 8 weeks. Rats in the control group were given normal rat pellet only while in treated groups, 15% of additional different vegetable oils were given. After 4 weeks of treatment the catalase (CAT) activity results showed that there was no significance difference (p > or = 0.05) between the control group and treated groups while after 8 weeks of treatment showed that there was no significant different (p > or = 0.05) between control group and RPO group but the treated rat liver with PO, CO and COC groups were the lowest and it were significantly lower (> or = 0.05) than control group. For superoxide dismutase (SOD) there was no significance difference (p > or = 0.05) between the control group and treated groups of vegetable oils after 4 and 8 weeks of treatment. Thus the study indicated that there was no significant (p > or = 0.05) effect on antioxidant enzyme (superoxide dismutase) but there was significant effect (p > or = 0.05) on catalase in rat liver.

Modulation of phase-II enzyme activities in benzene treated ovariectomized rats

The aim of the study was to determine the influence of ovariectomy on phase II enzymes viz. glutathione-S-transferase (GST), glutathione peroxidase (GPX) and catalase (CAT) in liver and kidney of female rats treated with benzene. The results showed the significant decrease of the GST and GPX activity in benzene treated rats after ovariectomy. However progesterone supplementation stimulated the activity of GST and GPX in liver and kidney of benzene treated non ovariectomized and ovariectomized rats. Progesterone supplementation to benzene treated ovariectomized rats helps to gain in CAT activity. Our results on DNA damage using single cell gel electrophoresis also confirmed our findings on antioxidant enzymes. The results showed that lack of protective progesterone against benzene toxicity is reflected in alterations in antioxidant enzyme activities. However progesterone therapy to benzene treated ovariectomized rats results in activating the antioxidant defence system. Since female workers are engaged in industrial sector, these results are important from occupational health point of view. Benzene exposure affects their reproductive health. Nevertheless, it could be modulated by suitable hormonal therapy.

Exacerbation of alcohol-induced oxidative stress in rats by polyunsaturated fatty acids and iron load

The hypothesis that excessive intake of vegetable oil containing polyunsaturated fatty acids and iron load precipitate alcohol-induced liver damage was investigated in a rat model. In order to elucidate the mechanism underlying this synergism, the serum levels of iron, total protein, serum glutamate pyruvate transaminase, liver thiobarbituric acid reactive substances, and activities of antioxidant enzymes superoxide dismutase, catalase in liver of rats treated with alcohol, polyunsaturated fatty acids and iron per se and in combination were examined. Alcohol was fed to the rats at a level of 10-30% (blood alcohol was maintained between 150-350 mg/dl by using head space gas chromatography), polyunsaturated fatty acids at a level of 15% of diet and carbonyl iron 1.5-2% of diet per se and in combination to different groups for 30 days. Hepatotoxicity was assessed by measuring serum glutamate pyruvate transaminase, which was elevated and serum total protein, which was decreased significantly in rats fed with a combination of alcohol, polyunsaturated fatty acids and iron. It was also associated with increased lipid peroxidation and disruption of antioxidant defense in combination fed rats as compared to rats fed with alcohol or polyunsaturated fatty acids or iron. The present study revealed significant exacerbation of the alcohol-induced oxidative stress in presence of polyunsaturated fatty acids and iron.

Hepatoprotection by carotenoids in isoniazid–rifampicin induced hepatic injury in rats

This study evaluates the hepatoprotective effect of carotenoids against isoniazid (INH) and rifampicin (RIF). Thirty-six adult rats were divided into the following 4 groups: (1) control group treated with normal saline; (2) INH + RIF group treated with 50mg·(kg body mass)-1·day-1 of INH and RIF each; (3) INH + RIF+ carotenoids group treated with 50mg·(kg body mass)-1·day-1 of INH and RIF each and 10mg·(kg body mass)-1·day-1 of carotenoids; and (4) carotenoids group treated with 10mg·(kg body mass)-1·day-1 of carotenoids for 28days intragastrically. Oxidative stress and antioxidant levels in liver and blood, liver histology and change in transaminases were measured in all the above-mentioned groups. There was an increase in lipid peroxidation with a reduction in thiols, catalase, and superoxide dismutase (SOD) in the liver and blood of rats accompanied by an increase in transaminases, bilirubin, and alkaline phosphatase. Treatment with carotenoids along with INH + RIF partially reversed lipid peroxidation, thiols, catalase, and SOD in the liver and blood of rats. Elevated levels of the enzymes in serum were also reversed partially by this treatment. The degree of necrosis, portal triaditis, and inflammation were also lowered in the carotenoids group. In conclusion, carotenoids supplementation in INH + RIF treated rats showed partial protection.

Investigations on the fluorescence quenching of 2,3-diazabicyclo[2.2.2]oct-2-ene by certain flavonoids

The fluorescence quenching of 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO) by seven flavonoids namely flavone, flavanone, quercetin, rutin, genistein, diadzein and chrysin has been investigated in acetonitrile and dichloromethane solvents. The bimolecular quenching rate constants lie in the range of 0.09–5.75 × 10 9 M −1 s −1 and are explained in terms of structure of the flavonoids studied. The reactivity of flavonoids are in the order: quercetin > rutin > genistein > diadzein > chrysin > flavone > flavanone. The quenching rate constants ( k q) increase with increase in the number of –OH groups. The endergonic thermodynamic values of Δ G et reveal that electron transfer quenching mechanism can be ruled out. Bond dissociation enthalpy calculations reveal that the position of –OH is important. Further in vitro-antioxidant activities of flavonoids were evaluated with rat liver catalase by gel electrophoresis. The deuterium isotope effect thus observed in this work provides evidence for hydrogen abstraction involved in the quenching process of singlet excited DBO by flavonoids. The data suggest the involvement of direct hydrogen atom transfer (radical scavenging) in the fluorescence quenching of DBO. Bond dissociation enthalpy calculation performed at B3LYP/6-31G(p′)//B3LYP/3-21G ∗ level are in excellent agreement with the above observations and further reveal that the number OH groups and position of them decide the quenching ability of the flavonoids.

Antioxidant and pancreas-protective effect of aucubin on rats with streptozotocin-induced diabetes

Oxidative stress has been suggested as a contributory factor in development and complication of diabetes. The aim of the present study was to determine the protective effect of aucubin on lipid peroxidation and activities of antioxidant defense systems and to conduct immunohistochemical evaluation of pancreas in streptozotocin-induced diabetic rats. Lipid peroxidation was determined by assessing the concentration of malondialdehyde and activities of antioxidant enzymes — catalase, glutathione peroxidase and superoxide dismutase in liver and kidneys of rats were determined. Changes of blood glucose and immunohistochemical evaluation on pancreas were also investigated as part of the pathology of diabetes. In our study, aucubin treatment lowered blood glucose. Diabetic rats exhibited an increase in the level of lipid peroxidation and decrease in activities of antioxidant enzymes in liver and kidneys as compared to control rats. Administration of aucubin to diabetic rats for 15 days significantly reversed damage associated with diabetes. In addition, diabetic rats showed an obvious decrease in insulin immunoreactivity and the number of β cells in pancreas, but the pancreas of aucubin-treated rats were improved and the number of immunoreactive β cells were significantly increased. These results indicated that aucubin may have value as a safe preventive or therapeutic agent against diabetes mellitus.