Myricitrin protects against peroxynitrite-mediated DNA damage and cytotoxicity in astrocytes

Peroxynitrite, a potent oxidising and nitrating species, has been implicated in the pathogenesis of neurodegenerative diseases. This study was undertaken to investigate the protective effect of myricitrin on peroxynitrite-mediated toxicity and the underlying mechanism. Our results showed that the presence of myricitrin was found to significantly inhibit peroxynitrite-mediated DNA damage. EPR spectroscopy demonstrated that myricitrin potently diminished the DMPO-hydroxyl radical adduct signal from peroxynitrite. Further study showed that glutathione (GSH) depletion caused by peroxynitrite can be effectively prevented by pre-incubation of astrocytes with myricitrin. Moreover, co-incubation of astrocytes with myricitrin and buthionine sulfoximine (BSO) eliminated the myricitrin-induced GSH increase. In contrast, co-incubation of myricitrin with BSO slightly protected astrocytes against cytotoxicity and DNA damage mediated by peroxynitrite. These results revealed that myricitrin can protect against peroxynitrite-induced DNA damage and cytotoxicity, which might have implications for myricitrin-mediated neuroprotection.     

Goat milk during iron repletion improves bone turnover impaired by severe iron deficiency

The effect of goat or cow milk-based diets, with either normal Fe content or an Fe overload, on bone turnover and the mineralization process was studied in control and anemic rats during chronic Fe repletion. One hundred eighty male Wistar rats were studied during a pre-experimental period of 40 d in which they were randomly divided into 2 groups, a control group receiving the AIN-93G diet with normal Fe content (45 mg/kg of diet) and the Fe-deficient group receiving the AIN-93G diet with low Fe content (5 mg/kg of diet) for 40 d. After the pre-experimental period, the rats were fed for 10, 30, or 50 d with goat or cow milk-based diets with a normal Fe content (45 mg/kg of diet) or an Fe overload (450 mg/kg of diet). In anemic rats, goat milk with normal Fe content increased levels of the biomarker of bone formation N-terminal propeptides of type I procollagen and diminished parathyroid hormone levels after only 10 d of supplying this diet, indicating the beginning of restoration of the bone demineralization induced by the anemia, which was not observed with cow milk. After 30 d of supplying the milk-based diets with normal Fe content or an Fe overload, biomarkers of bone formation and bone resorption were not different between control and anemic rats, indicating that the bone demineralization induced by the Fe-deficiency anemia had recovered, although the process of stabilization of bone turnover began earlier in the animals fed goat milk. In addition, a higher Ca deposit was observed in femur, which positively affects bone mineralization, as well as an increase of Fe in sternum, which indicates that the hematopoietic process essentially recovered earlier on the goat milk diet compared with the cow milk diet.     

Sesame lignan sesamol protects against aspirin-induced gastric mucosal damage in rats

Non-steroidal anti-inflammatory drugs are commonly used to control pain, fever, and various inflammatory diseases; however, they have been identified as gastro-toxic. The aim of the present study was to evaluate the effect of aspirin plus sesamol on gastric mucosa in rats. Rats were given oral aspirin (30 mg/kg/d) and oral sesamol (ranging from 0 to 30 mg/kg/day) for 5 weeks, after which their gastric mucosal integrity, oxidative stress, inflammation, and neutrophil infiltration were assessed 6 h after gastric surgery. Sesamol dose-dependently decreased aspirin-induced gastric haemorrhage and mucosal ulceration, and significantly reduced (a) gastric mucosal lipid peroxidation, (b) nitric oxide production, (c) gastric mucosal proinflammatory cytokines (tumor necrosis factor-α and interleukin 1-β levels), and (d) the activity of gastric mucosal myeloperoxidase compared with aspirin-alone groups. We hypothesize that aspirin plus sesamol decreases aspirin-induced gastro-toxicity by inhibiting neutrophil infiltration and subsequent gastric mucosal inflammation and oxidative stress in rats.     

Aloysia triphylla infusion protects rats against dextran sulfate sodium-induced colonic damage

BACKGROUND: Inflammatory bowel diseases consist of uncontrolled intestinal inflammation leading to mucosal disruption. Polyphenols are micronutrients with antioxidant and anti‐inflammatory properties and may play an interesting role in the prevention of intestinal inflammation. Lemon verbena (Aloysia triphylla (L'Herit.) Britton, Verbenaceae) infusion is a popular herbal drink rich in polyphenols. This study evaluated the protective effects of lemon verbena infusion consumption on the development of dextran sulfate sodium (DSS)‐induced colitis in rats. The infusion was given to rats as a drink providing 82 µmol polyphenols day^?1 for 21 days. Colitis was induced with 40 g l^?1 DSS in the drink for the last 7 days. RESULTS: Lemon verbena infusion treatment restored body weight gain and prevented colonic shortening. Despite no protective effect on myeloperoxidase activity, A. triphylla infusion limited histological colonic alterations. CONCLUSION: The results suggest that lemon verbena infusion partially protects rats against DSS‐induced inflammation. Copyright © 2011 Society of Chemical Industry     

Calcium-supplemented goat milk does not interfere with iron absorption in rats with anaemia induced by dietary iron depletion

The short-term effects of Ca-supplemented goat or cow milk on the nutritive utilization of Fe were evaluated in a metabolic balance study of rats with nutritional ferropenic anaemia (NFA). Control and Fe-deficient rats were fed for 14 d with goat or cow milk diets containing high-Ca content (10,000 mg/kg diet). The consumption of diets containing high levels of Ca for 14 d had no adverse effects on Fe absorption when the goat milk-based diet was provided, whereas for the cow milk-based diet, there was a significant fall in the apparent digestibility coefficient (ADC) of Fe. Moreover, the ADC and Fe retention/intake ratio (R/I) were higher in the anaemic rats fed the goat milk diet than among those fed the cow milk diet. These results suggest that despite a high dietary Ca content, goat milk minimizes Ca–Fe interactions and has no adverse effects on Fe absorption in rats with NFA.     

Dietary goat milk improves iron bioavailability in rats with induced ferropenic anaemia in comparison with cow milk

Using rats with induced iron (Fe)-deficiency anaemia, this study investigated the effects of diets based on goat milk (GM) or cow milk (CM) lyophilates on the nutritive utilization of Fe, its deposit in target organs and haematic parameters involved in Fe metabolism. GM improved Fe metabolism, especially in Fe-deficient rats, leading to a higher Fe content in the spleen, liver, sternum and femur in comparison with CM. After feeding the rats for 2 weeks with the different diets, the anaemia had decreased, especially with GM, as assessed by higher haemoglobin regeneration efficiency (HRE), serum Fe, red blood cells (RBC) and packed cellular volume (PCV) levels and lower platelet count. We conclude that dietary GM improves Fe bioavailability in both control and anaemic rats, increasing Fe deposits in target organs and favouring the recovery of haematological parameters after ferropenic nutritional anaemia.     

咖啡酸衍生物对自由基致DNA氧化损伤的联合保护作用

目的:探讨咖啡酸衍生物（CADs）:绿原酸（Chlorogenic acid,ChA）、阿魏酸（Ferulic acid,FeA）、迷迭香酸（Rosmarinic acid,RoA）对自由基致DNA损伤的联合抑制保护效果。方法:运用DPPH自由基及羟自由基反应模型观察不同组成的CADs对自由基的淬灭效应,以CuSO₄-Phen-VitC-H₂O₂-DNA化学发光体系测定不同成分的多酚类物质对·OH致DNA损伤的抑制作用。结果:在30min时间内,三种CADs联合组在浓度为25、50、100、200μg/mL时,对DPPH·清除率分别为28.93%、58.39%、83.93%和84.09%;对·OH清除率分别为33.43%、55.27%、71.23%、77.49%。在DNA化学发光体系中,在25～200μg/mL范围内,三种CADs联合组对DNA损伤产物发光抑制率为12.49%～81.09%。结论:CADs能有效清除DPPH自由基和羟自由基,抑制羟自由基引发的DNA损伤程度,并延迟其受损伤的时间。在各实验组中三种CADs联用组在对DPPH自由基清除率、DNA损伤产物发光抑制率以及保护DNA损伤的能力均最强,体现出协同作用。      

荞麦银耳复合饮料工艺优化及其对小鼠抗运动疲劳活性影响

目的：探讨银耳多糖（Tremella fuciformis polysaccharides,TFP）对小鼠力竭运动性氧化损伤的影响,并分析其机制。方法：采用TFP处理L6细胞48 h,CCK-8法检测L6的活力;L6细胞设置3组,包括对照组、H₂O₂组、H₂O₂+TFP组,孵育48 h,生化分析仪检测乳酸（Lactic Acid,LA）水平,Western blot实验检测Nrf2、NQO1和HO-1蛋白水平;将C57BL/6小鼠随机分为4组（每组n=10）,包括模型组、模型+TFP组（50、100、200 mg/kg）,模型+TFP组连续灌胃TFP,模型组灌胃相同剂量的蒸馏水,每天1次,连续2周。末次给药30 min后进行力竭运动,记录力竭游泳运动时间,采用酶联免疫吸附试验（ELISA）检测肝糖原（LG）、骨骼肌糖原（MG）;ELISA法检测血尿素氮（BUN）、LA、ROS、丙二醛（MDA）、超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GSH-Px）、TNF-α、IL-6、NF-κBp65水平。Western blot实验检测Nrf2、NQO1、HO-1蛋白水平。结果：H₂O₂组L6细胞的LA水平极显著（P<0.01）高于对照组,Nrf2、NQO1、HO-1蛋白水平极显著（P<0.01）低于对照组,TFP极显著（P<0.01）降低培养基中LA水平,极显著（P<0.01）上调L6细胞中Nrf2、NQO1、HO-1表达。TFP显著延长力竭游泳时间（P<0.05,P<0.01）,极显著降低LA（P<0.01）、BUN（P<0.05,P<0.01）水平,显著增加肝糖原（P<0.05,P<0.01）和肌糖原（P<0.05,P<0.01）水平,极显著上调SOD（P<0.01）、GSH-Px（P<0.01）,显著下调MDA（P<0.05,P<0.01）、ROS（P<0.01）水平,极显著（P<0.01）降低血清中TNF-α、IL-6、NF-κBp65的水平;与模型组比较,TFP显著增加Nrf2（P<0.05,P<0.01）、HO-1（P<0.05,P<0.01）、NQO-1（P<0.05,P<0.01）蛋白表达水平。结论：TFP通过抑制氧化应激、炎症改善力竭游泳运动引起的氧化损伤,其机制与调节Nrf2/HO-1信号通路相关。

     

Antioxidant activity in sugarcane juice and its protective role against radiation induced DNA damage

Sugarcane (Saccharum officinarum L.) juice is widely consumed by people of the tropics and subtropics. It has been used to cure jaundice and liver-related disorders in Indian systems of medicine. Its possible mechanism of action was examined in terms of antioxidant availability. The assays involved different levels of antioxidant action such as oxygen radical absorbance capacity (ORAC), radical scavenging abilities using 1,1-diphenyl-2-picryl hydrazyl (DPPH); 2,2′-azobis-3-ethyl benzthiazoline-6-sulfonic acid (ABTS); ferric reducing antioxidant power (FRAP); and protection of membranes examined by inhibition of lipid peroxidation. In addition, the content of phenols and total flavonoids were measured. The aqueous extracts of three varieties of sugarcane were studied. These varieties showed good antioxidant properties and were also able to protect against radiation induced DNA damage in pBR322 plasmid DNA and Escherishia coli cultures. In conclusion, the study reveals that the ability of sugarcane juice to scavenge free radicals, reduce iron complex and inhibit lipid peroxidation, may explain possible mechanisms by which sugarcane juice exhibits its beneficial effects in relation to its reported health benefits.     

Protective effects of solvent extracts from Taiwanese Agrocybe cylindracea strain B against DNA damage induced by environmental mutagens

Antioxidant activity of a water extract from Agrocybe cylindracea strain B (ACB) against iron‐mediated lipid peroxidation has been demonstrated. In addition, the protective effect of water extracts from ACB (WAC) on hydroxyl radical‐mediated DNA strand breaks was better than that of the shiitake mushroom (Lentinula edodes). Therefore, we decided to investigate whether different solvent extracts from ACB (ACES) protect DNA against oxidative stress induced by environmental mutagens, such as cooking oil fumes (COF) and benzo[a]pyrene (BaP). Oxidative DNA damage and intercellular DNA migration (tail length) were quantified by determining the decrease of extracellular supercoiled (SC) plasmid DNA and by using the ‘comet assay’ in the human adenocarcinoma CL‐3 cell line, respectively. IC₅₀ values of water, boiled water, methanol and acetone extracts from ACB were 108.97, 87.21, 970.52 and 1005.87 µg mL^?1, respectively, for the decrease in cupric/COF‐mediated SC plasmid DNA damage. The boiled water extract has the best protective effect. The ethyl acetate and ether extracts did not inhibit plasmid DNA damage. By using the comet assay, IC₅₀ values of the ether, methanol and acetone extracts from ACB were 672.95, 64.34, and 397.77 µg mL^?1, respectively, for the decrease in COF‐mediated DNA migration in CL‐3 cells. The methanol extract had the best protective effect. However, water, boiled water and ethyl acetate extracts from ACB showed no protective effect on COF‐mediated DNA migration. These results indicate that the protective capacity of ACES on DNA damage induced by environmental mutagens is different in pUC18 plasmid DNA and CL‐3 cell DNA. Copyright © 2006 Society of Chemical Industry     

Bioavailability of iron in goat milk compared with cow milk fed to anemic rats

Bioavailabilities of iron from dehydrated whole and skim goat milk were investigated using iron-deficient rats. Hemoglobin regeneration efficiencies were determined as the percent conversion of dietary iron into hemoglobin. The respective hemoglobin regeneration efficiencies for groups fed whole goat milk, whole cow milk, skim goat milk, and skim cow milk were 50.6, 13.1, 26.0, and 13.0%, indicating that iron bioavailability of goat milk was greater than cow milk. However, rats fed each milk had negative net increases in hemoglobin concentrations, implying that the iron contents of each milk were not adequate. For animals consuming whole goat milk supplemented with ferrous sulfate, the slope relating hemoglobin iron gained versus iron intake was .95. Respective bioavailabilities relative to ferrous sulfate were 54, 14, 28, and 14% for the four sources of milk. Iron bioavailability of goat milk is superior to cow milk when fed to anemic rats.