Protective effects of green tea polyphenol against reactive oxygen species-induced oxidative stress in cultured rat calvarial osteoblast

The injurious effects of reactive oxygen species on osteoblasts and the potential protective role played by green tea polyphenols (GtPP) were investigated using primarily cultured rat calvarial osteoblasts. Oxidative stress was induced in cultured osteoblasts, either by adding 100 mmol/L H2O2 or by the action of 40 U/L xanthine oxidase (XO) in the presence of xanthine (250 micromol/L). After incubation, the cellular viability, function and morphology were evaluated. Both treatments produced a significant reduction in osteoblast viability, as assessed by a two-colored fluorescence staining method combined with flow cytometric analysis and MTT assay. A significant reduction in the alkaline phosphatase activity was observed after H2O2 addition, whereas XO did not have the same effect. On the microscopic observations, the morphological changes and intracellular ultrastructural damages were remarkably induced by both treatments. The H2O2-induced alterations were prevented by pre-incubating the osteoblasts with 200 microg/ml GtPP for 1 h. When the oxidative stress was induced by XO, the cellular viability and morphology was also maintained at the same polyphenol concentration. These results demonstrate that GtPP can act as a biological antioxidant in a cell culture experimental model and protect cells from oxidative stress-induced toxicity.     

Therapeutic effect of green tea extract on oxidative stress in aorta and heart of streptozotocin diabetic rats

Hyperglycemia induced oxidative stress has been proposed as a cause of many complications of diabetes including cardiac dysfunction. The present study depicts the therapeutic effect of green tea extract on oxidative stress in aorta as well as heart of streptozotocin diabetic rats. Six weeks after diabetes induction, green tea was administered orally for 4 weeks [300 mg (kg body weight)(-1) day (-1)]. In aorta and heart of diabetic rats there was a significant increase in the activity of superoxide dismutase, catalase and glutathione peroxidase with an increase in lipid peroxides. Diabetic rats showed a significant decrease in the levels of serum and cardiac glutathione. Green tea administration to diabetic rats reduced lipid peroxides and activity of antioxidant enzymes whereas increased glutathione content. The results demonstrate that the induction of antioxidant enzymes in diabetic rats is not efficient and sufficient to reduce the oxidative stress. But green tea by providing a competent antioxidative mechanism ameliorates the oxidative stress in the aorta and heart of diabetic rats. The study suggests that green tea may provide a useful therapeutic option in the reversal of oxidative stress induced cardiac dysfunction in diabetes mellitus.     

Protection of osteoblastic cells from freeze/thaw cycle-induced oxidative stress by green tea polyphenol

Green tea polyphenol (GTP) together with dimethylsulphoxide (DMSO) were added to a freezing solution of osteoblastic cells (rat calvarial osteoblasts and human osteosarcoma cells) exposed to repeated freeze/thaw cycles (FTC) to induce oxidative stress. When cells were subjected to 3 FTCs, freezing medium containing 10% (v/v) DMSO and 500 μg GTP ml⁻¹ significantly (p < 0.05) suppressed cell detachment and growth inhibition by over 63% and protected cell morphology. Furthermore, the alkaline phosphatase activity of osteoblastic cells was appreciably maintained after 2 and 3 FTCs in this mixture. Polyphenols may thus be of use as a cell cryopreservant and be advantageous in such fields as cell transplantation and tissue engineering.     

银杏叶提取物对对乙酰氨基酚诱导的小鼠急性肝损伤的保护作用

目的：探究银杏叶提取物（GBE）对对乙酰氨基酚（APAP）诱导的小鼠急性肝损伤的保护作用及其机制。方法：30只小鼠随机分为对照组、模型组、GBE低、中、高剂量组（50,100,and 200 mg·kg^-1）,每组6只。除对照组外,剩余小鼠腹腔注射APAP （300 mg/kg）一次,随后GBE低、中、高剂量组按照相应剂量灌胃给药,治疗2 d后取材。观察各组肝脏大体情况和肝组织的病理组织学变化;取血测定各组小鼠血清中ALT、AST的活性和TNF-α、IL-6的水平;取肝检测各组肝组织中SOD、MPO的活性和GSH、MDA的含量;通过Western blot检测各组肝组织中Nrf2、HO-1蛋白的表达量。结果：与对照组相比,模型组肝脏明显肿大,病理表现差,血清中ALT、AST、TNF-α、IL-6的水平显著升高（P<0.01）,肝组织中GSH的含量和SOD的活性显著降低（P<0.01）,MDA的含量和MPO的活性显著升高（P<0.01）,Nrf2、HO-1蛋白表达明显下调（P<0.01）。与模型组相比,GBE组肝脏肿大减轻,病理表现有所改善,血清中ALT、AST、TNF-α、IL-6的水平显著降低（P<0.01）,肝组织中GSH的含量和SOD的活性显著提高（P<0.01）,MDA的含量和MPO的活性显著降低（P<0.01）,Nrf2、HO-1蛋白表达上调（P<0.05）,其中高剂量GBE组治疗效果最明显。结论：GBE可对APAP诱导的小鼠急性肝损伤具有保护作用,其作用机制可能是通过Nrf2/HO-1抗氧化途径发挥作用。     

Green tea polyphenol extract attenuates lung injury in experimental model of carrageenan-induced pleurisy in mice

Here we investigate the effects of the green tea extract in an animal model of acute inflammation, carrageenan-induced pleurisy. We report here that green tea extract (given at 25 mg/kg i.p. bolus 1 h prior to carrageenan), exerts potent anti-inflammatory effects in an animal model of acute inflammation in vivo.Injection of carrageenan (2%) into the pleural cavity of mice elicited an acute inflammatory response characterized by fluid accumulation in the pleural cavity that contained many neutrophils (PMNs), an infiltration of PMNs in lung tissues and increased production of nitrite/nitrate, tumour necrosis factor alpha. All parameters of inflammation were attenuated by green tea extract treatment. Furthermore, carrageenan induced an up-regulation of the adhesion molecule ICAM-1, as well as nitrotyrosine and poly (ADP-ribose) synthetase (PARS) formation, as determined by immunohistochemical analysis of lung tissues. Staining for the ICAM-1, nitrotyrosine, and PARS was reduced by green tea extract.Our results clearly demonstrate that treatment with green tea extract exerts a protective effect and offers a novel therapeutic approach for the management of lung injury.     

Selection of antioxidants against ovarian oxidative stress in mouse model

Oxidative stress (OS) plays an important role in the process of ovarian granulosa cell apoptosis and follicular atresia. The aim of this study was to select antioxidant against OS in ovary tissue. Firstly, we chose the six antioxidants and analyzed the reactive oxygen species (ROS) level in the ovary tissue. The results showed that proanthocyanidins, gallic acid, curcumin, and carotene decrease the ROS level compared with control group. We further demonstrated that both proanthocyanidins and gallic acid increase the antioxidant enzymes activity. Moreover, change in the ROS level was not observed in proanthocyanidins and gallic acid group of brain, liver, spleen, and kidney tissues. Finally, we found that proanthocyanidins and gallic acid inhibit pro‐apoptotic genes expression in granulosa cells. Taken together, proanthocyanidins and gallic acid may be the most acceptable and optimal antioxidants specifically against ovarian OS and also may be involved in the inhibition of granulosa cells apoptosis in mouse ovary.     

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.     

The antioxidant effect of Green Tea Mega EGCG against electromagnetic radiation-induced oxidative stress in the hippocampus and striatum of rats

Electromagnetic radiation (EMR) of cellular phones may affect biological systems by increasing free radicals and changing the antioxidant defense systems of tissues, eventually leading to oxidative stress. Green tea has recently attracted significant attention due to its health benefits in a variety of disorders, ranging from cancer to weight loss. Thus, the aim of the present study was to investigate the effect of EMR (frequency 900 MHz modulated at 217 Hz, power density 0.02 mW/cm², SAR 1.245 W/kg) on different oxidative stress parameters in the hippocampus and striatum of adult rats. This study also extends to evaluate the therapeutic effect of green tea mega EGCG on the previous parameters in animals exposed to EMR after and during EMR exposure. The experimental animals were divided into four groups: EMR-exposed animals, animals treated with green tea mega EGCG after 2 months of EMR exposure, animals treated with green tea mega EGCG during EMR exposure and control animals. EMR exposure resulted in oxidative stress in the hippocampus and striatum as evident from the disturbances in oxidant and antioxidant parameters. Co-administration of green tea mega EGCG at the beginning of EMR exposure for 2 and 3 months had more beneficial effect against EMR-induced oxidative stress than oral administration of green tea mega EGCG after 2 months of exposure. This recommends the use of green tea before any stressor to attenuate the state of oxidative stress and stimulate the antioxidant mechanism of the brain.     

Protective effects of ellagic and chlorogenic acids against oxidative stress in PC12 cells

Following exposure of differentiated neuronal PC12 cells to either t-BHP, hydrogen peroxide (H₂O₂) or FeSO₄ various kinds of reactive oxygen species (ROS) are generated leading to oxidative injury. The protective effects of two plant polyphenols, ellagic (EC) and chlorogenic acid (CGA), as well as of two metabolites, caffeic acid (CA) and ferulic acid (FA), were investigated in preincubation and coincubation experiments with respect to the following parameters: prevention of cell death, GSH depletion, lipid peroxidation and ROS formation.

The polyphenols more efficiently suppressed cytotoxicity and loss of GSH caused by peroxides than by iron, particularly in preincubation. Lipid peroxidation which increased much stronger in response to FeSO₄ was counteracted completely by the polyphenols. In case of iron, however, only coincubation was effective. EA and CGA and the metabolites CA and FA showed excellent elimination of ROS induced by all stressors. These findings suggest that two dietary antioxidants, EA and CGA, may have protective properties against oxidative stress induced in CNS.     

Protective effects of ellagic and chlorogenic acids against oxidative stress in PC12 cells

Following exposure of differentiated neuronal PC12 cells to either t-BHP, hydrogen peroxide (H₂O₂) or FeSO₄ various kinds of reactive oxygen species (ROS) are generated leading to oxidative injury. The protective effects of two plant polyphenols, ellagic (EC) and chlorogenic acid (CGA), as well as of two metabolites, caffeic acid (CA) and ferulic acid (FA), were investigated in preincubation and coincubation experiments with respect to the following parameters: prevention of cell death, GSH depletion, lipid peroxidation and ROS formation.

The polyphenols more efficiently suppressed cytotoxicity and loss of GSH caused by peroxides than by iron, particularly in preincubation. Lipid peroxidation which increased much stronger in response to FeSO₄ was counteracted completely by the polyphenols. In case of iron, however, only coincubation was effective. EA and CGA and the metabolites CA and FA showed excellent elimination of ROS induced by all stressors. These findings suggest that two dietary antioxidants, EA and CGA, may have protective properties against oxidative stress induced in CNS.     

Protective effect of Argan oil on mitochondrial function and oxidative stress against acrylamide-induced liver and kidney injury in rats

Abstract

Context

Acrylamide (ACR) is now a risk for general public health. Argan oil (AO) is harvested from the fruits of Argania spinosa and its rich source of antioxidant and phenolic compounds.     

Effect of Terminalia chebula aqueous extract on oxidative stress and antioxidant status in the liver and kidney of young and aged rats

We evaluated the preventive effects of Terminalia chebula (T. chebula) aqueous extract on oxidative and antioxidative status in liver and kidney of aged rats compared to young albino rats. The concentrations of malondialdehyde (MDA), lipofuscin (LF), protein carbonyls (PCO), activities of xantione oxidase (XO), manganese‐superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione‐S‐transferase (GST), and glucose‐6‐phosphate dehydrogenase (G6PDH), levels of glutathione (GSH), vitamin C and vitamin E were used as biomarkers. In the liver and kidney of aged animals, enhanced oxidative stress was accompanied by compromised antioxidant defences. Administration of aqueous extract of T. cheubla effectively modulated oxidative stress and enhanced antioxidant status in the liver and kidney of aged rats. The results of the present study demonstrate that aqueous extract of T. cheubla inhibits the development of age‐induced damages by protecting against oxidative stress. Copyright © 2009 John Wiley & Sons, Ltd.     

Dietary supplementation of a high-temperature-processed green tea extract attenuates cognitive impairment in PS2 and Tg2576 mice

ABSTRACT

Green tea intake is generally recognized as an effective supplement that promotes mental clarity and cognitive function. These health benefits of green tea have been attributed mainly to its effective component, epigallocatechin gallate (EGCG). Because various catechin derivatives potently enhance these health benefits, we manipulated the extraction process with a high-temperature intervention. High-temperature-processed green tea extract (HTP-GTE) showed an elevated proportion of gallocatechin gallate (GCG) content. To investigate the preventive effects of HTP-GTE on cognitive decline, we found its neuroprotective effects against amyloid β (Aβ)-induced neurotoxicity in neurons and clarified that GCG significantly inhibited Aβ aggregation in vitro. Moreover, we showed that HTP-GTE intake attenuated several cognitive-decline phenotypes in a model mouse of Alzheimer’s disease. These beneficial effects of HTP-GTE against cognitive decline were due to the distinctive composition of the extract and suggest the possibility that HTP-GTE supplementation could attenuate cognitive decline of Alzheimer’s disease.     

A novel optimized eco-friendly simple spectrofluorimetric method for the determination of total catechins in green tea extract: Application to commercial tablet

Green tea extract (GTE) contains antioxidants that are present in green tea. The active constituents of green tea extract are catechins. This study demonstrates a spectrofluorimetric method for measuring GTE's catechin concentration based on its native fluorescence. To design a quick, sensitive, and ecological spectrofluorimetric approach, all features were investigated and adjusted. This method relies on determining the GTE ethanolic solution's native fluorescence at 312 nm after excitation at 227 nm. The calibration graph displayed a linear regression for values between 0.05 and 1.0 μg mL⁻¹. The detection and quantification limits of the proposed technique were 0.008 and 0.026 μg mL⁻¹, respectively. Two pure catechins present in GTE, (−)-epicatechin and (−)-epigallocatechin gallate, were examined by the proposed method. The analytical estimation of GTE in the pharmaceutical tablet was achieved effectively using this approach. An adequate degree of agreement was found when the findings were compared to those obtained by the comparative technique. Therefore, the novel strategy may be used in the GTE quality control study with minimal risks to people or the environment. The quantum yields of catechins were estimated. The validated technique was accepted by the International Council of Harmonization criteria.     

Protective effect of Zizyphus lotus jujube fruits against cypermethrin-induced oxidative stress and neurotoxicity in mice

Context: Cypermethrin (CYP) is a synthetic pyrethroid insecticide used worldwide in agriculture, home pest control. The toxicity of CYP is well studied in many organisms.

Objective: The aim of present study was to investigate the protective effect of Zizyphus lotus (Zizyp) fruit against neurotoxicity and oxidative stress induced by CYP in mice.

Materials and methods: Mice were divided into four groups of six each: groups I and II were used as control and CYP control (20?mg/kg body weight). While, groups III was orally treated with Zizyphus lotus fruit (5?g/kg body weight) plus CYP (20?mg/kg body weight) for 18?days. Furthermore, HPLC–ESI–MS–MS (Q-Tof) and GC–MS were used to identify the compounds fraction.

Results: Antioxidant enzyme catalase (CAT), neurotoxicity enzyme acetylcholinesterase (AChE) activities and hydrogen peroxide (H₂O₂)_, malondialdehyde (MDA) levels were determined in the liver, kidney and heart. CYP caused decreased CAT activity, inhibition of AChE activity and increased the levels of H₂O₂ and MDA in heart, liver and kidney.

Conclusion: Our results indicate that Zizyp fruit is markedly effective in protecting mice against CYP-induced biochemical changes. This protection may be due to its antioxidant property and scavenging ability against active free radicals.     

Protective effect of Piper betle leaf extract against cadmium-induced oxidative stress and hepatic dysfunction in rats

The present study was undertaken to examine the attenuative effect of Piper betle leaf extract (PBE) against cadmium (Cd) induced oxidative hepatic dysfunction in the liver of rats. Pre-oral supplementation of PBE (200 mg/kg BW) treated rats showed the protective efficacy against Cd induced hepatic oxidative stress. Oral administration of Cd (5 mg/kg BW) for four weeks to rats significantly (P > 0.05) elevated the level of serum hepatic markers such as serum aspartate transaminase (AST), serum alanine transaminase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), gamma-glutamyl transpeptidase (GGT), bilirubin (TBRNs), oxidative stress markers viz., thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides (LOOH), protein carbonyls (PC) and conjugated dienes (CD) and significantly (P > 0.05) reduced the enzymatic antioxidants viz., superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione reductase (GR) and glucose-6-phosphate dehydrogenase (G6PD) and non-enzymatic antioxidants Viz., reduced glutathione (GSH), total sulfhydryls (TSH), vitamin C and vitamin E in the liver. Pre-oral supplementation of PBE (200 mg/kg BW) in Cd intoxicated rats, the altered biochemical indices and pathological changes were recovered significantly (P > 0.05) which showed ameliorative effect of PBE against Cd induced hepatic oxidative stress. From the above findings, we suggested that the pre-administration of P. betle leaf extract exhibited remarkable protective effects against cadmium-induced oxidative hepatic injury in rats.     

Protective effect of alpha-tocopherol on oxidative stress in experimental pulmonary fibrosis in rats

The study was undertaken to investigate the influence of alpha-tocopherol (vitamin E) on malondialdehyde (MDA) and glutathione (GSH) levels and catalase (CAT) activity in lung of rats with bleomycin-induced pulmonary fibrosis (PF). Fourteen Wistar-albino rats were randomly divided into two groups of seven animals each. The first group was treated intra-tracheally with bleomycin hydrochloride (BM group); the second group was also instilled with BM but received injections of alpha-tocopherol twice a week (BM + E group). The third group was treated in the same manner with saline solution only, acting as controls (C). There were decreases in GSH level and CAT activity while an increase in MDA level in BM group was found compared to the control group (p < 0.05). Vitamin E had a regulator effect on these parameters. After administration of alpha-tocopherol, the increase in GSH level and CAT activity and the decrease in MDA level were seen in BM + E group compared to BM group (p < 0.05). Distinct histopathological changes were found in the BM group compared to the untreated rats. Less severe fibrotic lesions were also observed in the BM + E group. The results show that vitamin E is effective on the prevention of BM-induced PF, as indicated by differences in the lung levels of oxidants and antioxidants.     

Protective effect of green tea against lipid peroxidation in the rat liver, blood serum and the brain

This paper reports data on the effect of green tea on the lipid peroxidation products formation and parameters of antioxidative system of the liver, blood serum and central nervous tissue of healthy young rats drinking green tea for five weeks. The rats were permitted free access to solubilized extract of green tea. Bioactive ingredients of green tea extract caused in the liver an increase in the activity of glutathione peroxidase and glutathione reductase and in the content of reduced glutathione as well as marked decrease in lipid hydroperoxides (LOOH), 4-hydroksynonenal (4-HNE) and malondialdehyde (MDA). The concentration of vitamin A increased by about 40%. Minor changes in the measured parameters were observed in the blood serum. GSH content increased slightly, whereas the index of the total antioxidant status increased significantly. In contrast, the lipid peroxidation products, particularly MDA was significantly diminished. In the central nervous tissue the activity of superoxide dismutase and glutathione peroxidase decreased while the activity od glutathione reductase and catalase increased after drinking green tea. Moreover the level of LOOH, 4-HNE and MDA significantly decreased. The use of green tea extract appeared to be beneficial to rats in reducing lipid peroxidation products. These results support and substantiate traditional consumption of green tea as protection against lipid peroxidation in the liver, blood serum, and central nervous tissue.     

Protective effect of hypoglycemic granule against diabetes-induced liver injury by alleviating glycolipid metabolic disorder and oxidative stress

The current study was designed to explore the therapeutic effect and mechanism of different extraction, which came from hypoglycemic granule on diabetes-induced liver injury. The ethanol fraction (HGEF) and aqueous fraction (HGAF) from hypoglycemic granule were prepared and administered p.o. to diabetic mice for 17 weeks after 6 weeks of constructing the model. Hematoxylin-eosin (HE) staining and periodic acid-Schiff (PAS) staining were individually applied to observe the morphological change and glycogen deposition. In addition, Oil Red O staining was adopted in lipid droplets detection. Western blot analysis was performed to evaluate the protein expression. The commercial biochemical kits were used to determine the fasting blood glucose value, enzyme activity, and some biochemical indicators. HGEF not only significantly decreased the levels of blood glucose, the content of triglycerides, total cholesterol, low-density lipoprotein, and lipid droplet accumulation, but also remarkably enhanced the high-density lipoprotein, glycogen synthesis, and further improved the hepatic function in diabetic mice. Moreover, HGEF increased the superoxide dismutase (SOD) activity and inhibited the malondialdehyde production, so did HGAF. HGAF performed potential to modulate lipid metabolism via decreasing TG and LDL levels. Further, the protein expressions of SOD, nuclear factor erythroid 2-related factor 2 (Nrf2), and forkhead box O3 (Foxo3a) were increased by HGEF, whereas the receptor-interacting serine-threonine kinase 3 (RIP3), calcium/calmodulin-dependent protein kinase II (CaMKII), and cytochrome c (Cyt c) expressions were inhibited. Our present results suggest that HGEF has superiority in ameliorating oxidative stress via modulating hepatic glycolipid metabolism homeostasis in low-dose streptozotocin-induced liver tissue of diabetic mice.     

Neopterin and oxidative stress markers in the diagnosis of extrapulmonary tuberculosis

Background: Extrapulmonary tuberculosis (EPTB) often presents with nonspecific signs and symptoms. Further the paucibacillary nature of extrapulmonary specimens and irregular distribution of bacilli lower the sensitivity of conventional diagnostic methods making EPTB, a diagnostic dilemma.

Objective: To study neopterin, protein carbonyl and malondialdehyde (MDA) in EPTB.

Methods: Sixty nine clinically confirmed cases with an equal number of age and sex matched healthy controls were enrolled. Ziehl–Neelsen staining for acid fast bacilli and culture on Lowenstein–Jensen medium were performed on all the extrapulmonary specimens. Serum neopterin and protein carbonyl levels were estimated using commercial ELISA kits. Malondialdehyde was determined by measuring thiobarbituric acid reactive substances.

Results: Serum neopterin, protein carbonyl and MDA levels were significantly discriminative for cases of EPTB from healthy controls (p?<?0.05). Levels of all the three biomarkers under study significantly differed between culture as well as smear positive and negative cases. A positive correlation between neopterin and protein carbonyl was seen among the cases.

Conclusions: So far few studies have integrated combination of validated host biomarkers for active disease in EPTB. Our study suggests the potential diagnostic role of neopterin, protein carbonyl and MDA in EPTB.