杠板归抗氧化作用及抑制α-葡萄糖苷酶活性

目的:考察杠板归抗氧化及抑制α-葡萄糖苷酶活性作用。方法:通过对ABTS自由基和DPPH自由基的清除能力及FRAP法对杠板归的抗氧化活性进行评价。应用体外α-葡萄糖苷酶筛选模型进行杠板归酶抑制活力的测定。结果:杠板归乙酸乙酯和甲醇提取物具有一定的抗氧化活性,其中甲醇提取物抗氧化活性最好,在ABTS、DPPH和FRAP方法中的Trolox当量分别为701.60±25.35,338.66±11.26,392.52±12.89μmolTE·g-1。杠板归3种提取物均具有很好的抑制α-葡萄糖苷酶活性作用,其中甲醇提取物活性最好,IC50值为16.14 mg·L-1。结论:杠板归甲醇提取物的抗氧化和抑制α-葡萄糖苷酶活性均最好,推测其可以用于糖尿病的治疗。     

Oat-based breakfast cereals are a rich source of polyphenols and high in antioxidant potential

Oats are a rich source of β-glucans and bioactive phytochemicals. The established health-beneficial properties of oats have led to an increase in the consumption of oats and oat-based food products in recent years. The objective of the present study was to analyse and compare the polyphenol content and total antioxidant capacity (via FRAP (ferric ion reducing antioxidant power) and DPPH (2,2-diphenyl-1-picrylhydrazyl) inhibition) of 30 commercially available oat-based breakfast cereals. All of the breakfast cereals analysed were a significant source of polyphenols (1506–1853 μg gallic acid equivalents (GAE)/g) and antioxidants (1682–3542 μmol/l FRAP; 30–201% inhibition of DPPH compared to gallic acid standard). There was little difference between premium and budget brand varieties of the breakfast cereals. The polyphenol levels in an average serving (40 g) of an oat-based breakfast cereal are comparable to those found in fruits and vegetables. Overall, our findings suggest that consumption of oat-based breakfast cereals could be a significant contributor to the total polyphenol content and antioxidant potential of the diet.     

Antioxidant and anti-neoplastic activities of Picrorhiza kurroa extracts

Picrorhizakurroa Royle ex Benth., a well-known traditional herb from the Scrophulariaceae family has a remarkable reputation among the indigenous medical practitioners. The antioxidant and anti-neoplastic activities of methanolic and aqueous extracts of P. kurroa rhizome were investigated in the present study. The total phenolic content was determined by a spectrophotometric method. The antioxidant efficacies of the extracts were studied employing radical scavenging assays (DPPH and OH), ferric reducing antioxidant property (FRAP) and thiobarbituric acid (TBA) assay for testing inhibition of lipid peroxidation. Furthermore, the cytotoxicity of the extracts was tested by XTT assay in MDA-MB-435S (human breast carcinoma), Hep3B (human hepatocellular carcinoma) and PC-3 (human prostate cancer) cell lines. The ability of the extracts to induce apoptosis was also investigated. Both extracts exhibited promising antioxidant potentials. The extracts were also observed to be cytotoxic at the tested dosage and were able to target cells towards apoptosis. The study concludes that P. kurroa possess diverse therapeutic potentials which might be useful in development of drugs or their precursors.     

Evaluation of oxidative status and depression-like responses in Brown Norway rats with acute myeloid leukemia

It has been proved that oxidative stress increases when leukemia is accompanied by depression. This fact may indicate the role of oxidative stress in the development of depression in cancer patients. The aim of this study was to determine whether the acute myeloid leukemia of Brown Norway rats, which is accompanied by oxidative stress, evoked behavioral and receptor changes resembling alterations characteristic of rat models of depression. The rats were divided into two groups: leukemic rats and healthy control. Leukemia was induced through intraperitoneal injection of 10⁷ promyelocytic leukemia cells to the Brown Norway rats. Depression-like behavior was evaluated in the forced swim test at 30 or 34 days after leukemic cells injection. The rats were killed after the evaluation and the spleen, brain cortex and hippocampus were excised. The red–ox state was assessed in homogenates of tissues by measuring total glutathione (GSH) content, the ferric ion reducing ability of plasma (FRAP) level, expression of heme oxygenase-1 (HO-1), biliverdin reductase (BvR) and ferritin mRNA, superoxide dismutase (SOD) activity, as well as malondialdehyde (MDA) concentration. Radioligand binding assay was used to assess of the effect of leukemia on cortical receptors. Leukemic cells were identified using RM-124 antibody by FACS Calibur flow cytometry. Leukemia influenced locomotory activity as well as forced swim test behavior in a 34-day series of experiments. Signs of oxidative stress in leukemic rats were observed in each examined stage of leukemia development. The FRAP values and glutathione contents, were significantly lowered whereas HO-1 mRNA expression, and malonodialdehyde concentrations were significantly increased in the spleen and brain structures of leukemic rats in comparison with the healthy controls. A significant increase in the potency of glycine to displace [³H]L-689,560 from the strychnine-insensitive glycine site of the N-methyl-D-aspartic (NMDA) receptors receptor complex in cortical homogenates of the leukemic rats in 30- and 34-day experimental series was observed in comparison with the control. Upregulation of 5-HT_2A receptors was observed in rat cortex after 30 days of leukemia development but not in 34-days series compared with the control. It is concluded that disturbances in antioxidant system in brain cortex were accompanied by an activation of glycine sites of the NMDA receptor complex, regardless of stage of leukemia development, which are characteristic of model of depression. Findings of our study demonstrate the link between glutamatergic activity, oxidative stress and leukemia.     

Postsynaptic protein mobility in dendritic spines: long-term regulation by synaptic NMDA receptor activation

Reorganization of molecular components represents a cellular mechanism for synaptic plasticity. Dendritic spines, major sites for glutamatergic synapses, compartmentalize dynamic changes in molecular composition. Here, we use fluorescence recovery after photobleaching (FRAP) in cultured hippocampal neurons to show that spine proteins undergo continual exchange with extra-spine pools. Each spine component has a distinctive mobility: calcium/calmodulin activated protein kinase CaMKIIalpha > GluR1 AMPA glutamate receptor > PSD-95 scaffolding protein > NR1 NMDA glutamate receptor. Stimulation of synaptic NMDA receptors by a protocol that induces chemical LTP resulted in a long-lasting reduction in the mobility of spine CaMKIIalpha and an increased mobile fraction but slower kinetics for spine GluR1. Stimulation also increased the resistance of postsynaptic CaMKIIalpha to detergent extraction. These results suggest long-lasting changes in affinity of protein-protein interactions and/or ongoing alterations in exo/endocytosis. Such lasting changes in protein mobility may contribute to maintaining alterations in synaptic efficacy.     

Octanol,a gap junction uncoupling agent,changes intracellular [H+] in rat astrocytes

Octanol rapidly closes gap junction channels but its mechanism of action is not known. Because intracellular [H⁺], pH_i, also affects the conductance of gap junctions, we studied octanol's effects on pH_i in cultured rat astrocytes, which are highly coupled cells. Octanol (1 mM) caused an acid shift in the pH_i of 90% of rat hippocampal astrocytes which averaged −0.19 ± 0.09 pH units in magnitude. In 58% of the cells tested, a biphasic change in pH_i was seen; octanol produced an initial acidification lasting ∼10 min that was followed by a persistent alkalinization. The related gap junction uncoupling agent, heptanol, had similar effects on pH_i. Octanol-induced changes in pH_i were similar in nominally HCO₃⁻-free and HCO₃⁻-containing solutions, although the rate of initial acidification was significantly greater in the presence of HCO₃⁻. The initial acidification was inhibited in the presence of the stilbene DIDS, an inhibitor of Na⁺/HCO₃⁻ cotransport, indicating that octanol caused acidification by blocking this powerful acid extruder. The alkalinization was inhibited by amiloride which blocks the Na⁺/H⁺ exchanger (NHE), an acid extruder, suggesting that the alkaline shift induced by octanol was caused by stimulation of NHE. As expected, octanol's effects on astrocytic pH_i were prevented by removal of external Na⁺, which blocks both Na⁺/HCO₃⁻ cotransport and NHE. Octanol had only small effects on intracellular Ca²⁺ (Ca²⁺_i) in astrocytes. Hepatocytes which, like astrocytes, are strongly coupled to one another, showed no change in pH_i with octanol application. Fluorescence recovery after photobleaching (FRAP) was used to study the effect of changes in astrocyte pH_i on degree of coupling in hippocampal astrocytes. Coupling was decreased by intracellular acid shifts ∼−0.2 pH units in size. Octanol's effects on astrocyte pH_i were complex but a prompt initial acidification was nearly always seen and could contribute to the uncoupling action of this drug in astrocytes. Because octanol uncouples hepatocytes without changing their pH_i, this compound clearly can influence gap junctional conductance independent of changes in pH_i. © 1996 Wiley-Liss, Inc.     

Microfluidic enhancement of intramedullary pressure increases interstitial fluid flow and inhibits bone loss in hindlimb suspended mice

Interstitial fluid flow (IFF) has been widely hypothesized to mediate skeletal adaptation to mechanical loading. Although a large body of in vitro evidence has demonstrated that fluid flow stimulates osteogenic and antiresorptive responses in bone cells, there is much less in vivo evidence that IFF mediates loading‐induced skeletal adaptation. This is due in large part to the challenges associated with decoupling IFF from matrix strain. In this study we describe a novel microfluidic system for generating dynamic intramedullary pressure (ImP) and IFF within the femurs of alert mice. By quantifying fluorescence recovery after photobleaching (FRAP) within individual lacunae, we show that microfluidic generation of dynamic ImP significantly increases IFF within the lacunocanalicular system. In addition, we demonstrate that dynamic pressure loading of the intramedullary compartment for 3 minutes per day significantly eliminates losses in trabecular and cortical bone mineral density in hindlimb suspended mice, enhances trabecular and cortical structural integrity, and increases endosteal bone formation rate. Unlike previously developed modalities for enhancing IFF in vivo, this is the first model that allows direct and dynamic modulation of ImP and skeletal IFF within mice. Given the large number of genetic tools for manipulating the mouse genome, this model is expected to serve as a powerful investigative tool in elucidating the role of IFF in skeletal adaptation to mechanical loading and molecular mechanisms mediating this process. © 2010 American Society for Bone and Mineral Research     

Effect of Dietary Fats on Oxidative-Antioxidative Status of Blood in Rats

This study was performed to examine the effect of different fat sources, lard, sunflower oil (SO), and fish oil (FO) in high-fat and low-fat diet on reactive oxygen species generation by blood phagocytes, glutathione redox status in erythrocytes, and total plasma antioxidant ability in rats. Whole blood chemiluminescence (CL) did not differ between three low-fat fed groups. However, baseline and phorbol myristate acetate (PMA)-stimulated CL in blood of high-lard fed rats were lower than in low-lard and high-SO fed animals. Phagocyte-stimulated oxidative burst was higher in rats fed high-SO diet than in those fed low-SO and high-FO diets. The highest level of oxidize glutathione (GSSH), the lowest reduce glutathione (GSH)/GSSG ratio in erythrocytes, and the highest plasma activity to reduce ferric ions were observed in rats fed both diets contaning linoleic acid-rich sunflower oil compared to animals fed the corresponding energy from other fats. 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity of plasma was lower in high-lard and high-FO fed rats compared to the corresponding low-fat diets, and the lowest in low-FO fed rats among low-fat fed animals. We presume from our results that linoleic acid may have dual effect, prooxidative in blood cells but maintaining total antioxidant plasma ability.     

Chemiluminescent Analysis of Plasma Antioxidant Capacity in Uremic Patients Undergoing Hemodialysis

Objective. Hemodialysis is a common therapeutic strategy for patients with end stage renal failure. During the hemodialytic process, the neutrophils are activated (neutrophil burst) due to the hemoincompatibility induced by hemodialysis. As a result, the activated neutrophils release reactive oxygen species (ROS), such as hydrogen peroxide, singlet oxygen, and hypochlorite, into the bloodstream and cause oxidative damage. Methods. This study investigated the antioxidant alteration of plasma in uremic patients undergoing hemodialysis by chemiluminescent analysis. The antioxidant capacities of plasma in scavenging hydrogen peroxide, singlet oxygen, and hypochlorite were investigated in this experiment. In addition, investigation of the ferric-reducing ability of plasma (FRAP) would be covered in this study as well. Results. This study found that after hemodialysis, the antioxidant capacities of plasma in scavenging hydrogen peroxide, singlet oxygen, and hypochlorite decreases 7.9%, 18.8%, and 18.9%, respectively. Moreover, the FRAP is reduced by 56%. We speculate that the loss of dialyzable solutes (such as uremic solutes and antioxidants with small molecular weight) in plasma resulted in its decrease in antioxidant capacity. Conclusion. We therefore suggest that the supplement of antioxidants with small molecular weight is capable of regaining antioxidant defense in plasma and preventing oxidative damage induced by hemodialysis.     

Therapeutic Potentials of Oroxylum indicum Bark Extracts

AIM:Diverse therapeutic potentials of methanolic and aqueous extracts of Oroxylum indicum(L.)Vent.bark,includ- ing antioxidant property,cytotoxicity and protection against oxidative DNA damage were investigated in this study.METHODS:Total phenolics in the extracts were determined by spectrophotometric method.Ferric reducing antioxidant property(FRAP),free radical (DPPH·and ·OH)scavenging activities,as well as inhibitory effect on lipid peroxidation have been investigated.Cytotoxicity of the extracts was inv...