Anti-glycative and anti-inflammatory effects of protocatechuic acid in brain of mice treated by d-galactose

Protocatechuic acid (PCA) at 0.5%, 1% or 2% was supplied to d-galactose (DG) treated mice for 8 week. PCA intake at 2% increased its deposit in brain. DG treatment increased brain level of reactive oxygen species, protein carbonyl, carboxymethyllysine, pentosidine, sorbitol, fructose and methylglyoxal (P < 0.05). PCA intake, at 1% and 2%, lowered brain level of these parameters (P < 0.05). DG treatments enhanced activity and protein expression of aldose reductase (AR) and sorbitol dehydrogenase, as well as declined glyoxalase I (GLI) activity and protein expression (P < 0.05). PCA intake at 1% and 2% reduced activity and protein expression of AR (P < 0.05), and at 2% restored GLI activity and expression (P < 0.05). DG injection also elevated cyclooxygenase (COX)-2 activity and expression, and increased the release of interleukin (IL)-1beta, IL-6, tumor necrosis factor-alpha and prostaglandin E₂ in brain (P < 0.05). PCA intake decreased these cytokines (P < 0.05), and at 1% and 2% suppressed COX-2 activity and expression (P < 0.05). PCA intake at 1% and 2% also lowered DG-induced elevation in activity, mRNA expression and protein production of nuclear factor kappa B p65 (P < 0.05). These findings suggest that the supplement of protocatechuic acid might be helpful for the prevention or alleviation of aging.     

Chemoprevention of liver cancer by plant polyphenols

Primary liver cancer or hepatocellular carcinoma (HCC) is one of the most frequent tumors representing the fifth commonest malignancy worldwide and the third cause of mortality from cancer. Currently, the treatments for HCC are not so effective and new strategies are needed for its fight. Chemoprevention, the use of natural or synthetic chemical agents to reverse, suppress or prevent carcinogenesis is considered an important way for confronting HCC. Many of the chemopreventive agents are phytochemicals, namely non-nutritive plant chemicals with protective or disease preventive properties. In this review, we focus on plant polyphenols, one of the most important classes of phytochemicals, their chemopreventive properties against HCC and discuss the molecular mechanisms accounting for this activity.     

The Association of Measures of the Micro- and Macro-Vasculature with Selenium and GPx Activity in a Young Bi-Ethnic Population: The African-PREDICT Study

Abstract

Objective: Selenium plays an important physiological role as component for antioxidant selenoproteins such as glutathione peroxidase (GPx). Since oxidative stress contributes to hypertension development, it is likely that selenium deficiency may contribute to the burden of cardiovascular disease. To better understand the involvement of selenium and GPx in the early development of cardiovascular disease, we investigated in young, healthy black and white African men and women whether measures of the micro- and macrovasculature are related to selenium and GPx activity.

Methods: In young adults (N?=?394; aged 20–30?years) we determined serum selenium, GPx activity, microvascular measures (central retinal artery equivalent, central retinal vein equivalent, arteriolar-to-venular ratio [AVR], and estimated glomerular filtration rate [eGFR]), and macrovascular measures (pulse wave velocity, 24-hour pulse pressure [PP] and augmentation index [Aix]).

Results: In multivariable-adjusted regression analyses, there were vasculoprotective associations between serum selenium and a microvascular measure (AVR [β?=?0.23; p?=?0.036]) in black African women and with a macrovascular measure (24-hour PP [β = ?0.15; p?=?0.048]) in white African women. In turn, GPx activity also showed a protective association with a microvascular measure (eGFR) in white African men (β?=?0.23; p?=?0.035), as well as with macrovascular measures (AIx, PP) in the black (β = ?0.25; p?=?0.027) and white African men (β = ?0.22; p?=?0.035), and black African women (β = ?0.32; p?=?0.001).

Conclusions: Collectively the findings suggest a protective role for the micronutrient selenium and GPx on both the micro- and macrovasculature in a young, healthy bi-ethnic population.     

Effects of methiocarb on lipid peroxidation and glutathione level in rat tissues

Methiocarb is an N-methylcarbamate insecticide used worldwide in agriculture and health programs. The aim of this study was to investigate the possible effects of methiocarb to induce lipid peroxidation (LPO) in tissues of male Wistar rats following single and repeated oral exposures. Animals were divided into six different groups, and methiocarb was administered by orally at doses 25, 10, and 2?mg/kg body weight for 1, 5, and 28 days, respectively. Liver, kidney, brain, and testis tissues were taken from the rats for the biochemical examinations. LPO and reduced glutathione (GSH) levels were determined in the tissues. LPO was significantly increased in liver, kidney, brain, and testis after 1-, 5-, and 28-day treatments of methiocarb. GSH levels were significantly increased in the 1-day period and significantly decreased in the 5- and 28-day periods in all tissues after methiocarb administration. It is concluded that methiocarb may induce LPO and produce disturbances on the GSH levels in liver, kidney, testis, and brain of rats. This suggests that methiocarb-induced toxicity may be associated with oxidative stress to cellular membranes. Further studies are required to better understand the role of oxidative stress on methiocarb-induced toxicity.     

还原型谷胱甘肽防治化疗药物性肝损害效果观察

目的：观察双益健（还原型谷胱甘肽）对恶性肿瘤患者接受化疗时并发的化疗药物性肝损害的预防和治疗作用。方法：采用前瞻性对照研究,将148例患者分为2组,预防组74例在化疗同时予以还原型谷胱甘肽;对照组74例单纯化疗,该组患者如出现肝损害则使用还原型谷胱甘肽治疗（30例）,观察比较两组患者在肝损害发生率及损害程度上的差异,并评价还原型谷胱甘肽治疗肝损害的疗效。结果：预防组比对照组在损害发生率低,有显著性差异（P〈0．01）;对照组中肝功能损害患者应用还原型谷胱甘肽治疗前后ALT,AST,FBIL及DBIL值变化有显著性差异（P〈0．01）。结论：还原型谷胱甘肽预防和治疗恶性肿瘤患者化疗药物性肝损害治疗有效。     

还原型谷胱甘肽治疗糖尿病肾病的临床观察

目的 研究还原型谷胱甘肽(GSH)对糖尿病肾病的治疗作用.方法 将符合入选条件的糖尿病肾病(微量尿白蛋白期)患者随机分为3组,用不同剂量的GSH治疗,3周后观察尿微量白蛋白、肌酐、尿素氮、空腹血糖、早餐后2 h血糖、糖化血红蛋白的变化.结果 中等剂量GSH对糖尿病肾病患者无明显的治疗作用,而大剂量GSH能显著减少糖尿病肾病患者的尿微量白蛋白的含量,但对肌酐、尿素氮、糖化血红蛋白、空腹及早餐后2 h血糖无明显影响.结论 还原型谷胱甘肽对糖尿病肾病有一定的治疗作用.     

茶多酚对阿霉素心脏毒性的保护作用及其机制的研究

 目的：探讨茶多酚(tea polyphenols,TP)减轻阿霉素心脏毒性的作用及其机制。方法：以病理记分法记录心肌损害程度;用TBA法测定大鼠心肌组织的脂质过氧化水平;用邻苯三酚自氧化法测定心肌组织、红细胞的SOD活力;用DTNB法测定心肌GSH-Px活力。结果：阿霉素两周累积用量16mg·kg^-1（第2天,第4天1mg·kg^-1;第6天,第8天2mg·kg^-1;第10天,第12天3mg·kg^-1;第14天4mg·kg^-1;ip可致大鼠心肌损害,心肌MDA水平升高,GSH-Px活性下降,心肌和红细胞SOD活性降低,TP28,56和84mg·kg^-1具有减轻阿霉素所致的大鼠心肌毒性作用。结论：茶多酚减轻阿霉素心肌毒性机制可能与其清除自由基作用、保护心肌SOD及GSH-Px活性有关,从而有效地对抗阿霉素引起的大鼠心肌脂质过氧化有关。     

高效液相 (HPLC) 荧光法同时测定人血浆中4种硫醇物的浓度

 目的  建立同时测定人血浆中半胱氨酸(cysteine,Cys)、同型半胱氨酸(homocysteine,Hcy)、半胱氨酰甘氨酸(cysteinylglycine,CysGly)和谷胱甘肽(glutathione,GSH)等4种硫醇物的高效液相色谱法(high-performance liquid chromatography,HPLC)。方法  血浆经磷酸盐缓冲液(phosphate buffered saline,PBS)稀释后,用三(2-羧乙基)膦盐酸盐［tris-(2-carboxyethyl)-phosphine hydrochloride,TCEP］还原,用三氯乙酸(trichloroacetic acid,TCA)溶液进行蛋白沉淀,再用7-氟苯呋咱-4-硫酸铵盐(7-fluorobenzofurazan-4-sulfonic acid ammonium salt,SBD-F)进行衍生化反应,荧光检测器检测。色谱条件:色谱柱为Kromasil C18 (250 mm×4.6 mm,5 μm),柱温29 ℃;流动相为甲醇:0.1 mol/L醋酸盐缓冲液(pH=4.5,3.5∶96.5,V/V),流速为0.8 mL/min,等度洗脱。激发波长385 nm,发射波长515 nm。采用外标法定量。结果  Cys、Hcy、CysGly和GSH的线性范围分别为50~800 μmol/L、4~64 μmol/L、10~160 μmol/L和2.5~40 μmol/L。Cys、Hcy、CysGly和GSH的最低检测浓度分别为2.5 μmol/L、1.0 μmol/L、1.0 μmol/L和1.0 μmol/L。各组分日内、日间精密度RSD均<12 %。平均回收率为95.01 %~116.17 %。结论  该方法具有检测时间短、灵敏性高、精密度和准确度好的特点,适用于临床人血浆中硫醇物浓度的常规检测。     

Role of Aggregatibacter actinomycetemcomitans in glutathione catabolism

Introduction:  Our previous studies demonstrated that three enzymes, γ-glutamyltransferase (GGT), cysteinylglycinase (CGase) and cystalysin, are required for the catabolism of glutathione to produce hydrogen sulfide (H₂S) in Treponema denticola . In this study, we examined glutathione catabolism in Aggregatibacter actinomycetemcomitans .
Methods:  The GGT and CGase of A. actinomycetemcomitans were determined by biological methods and GGT was characterized using a molecular biological approach.
Results:  A. actinomycetemcomitans showed GGT and CGase activity, but could not produce H₂S from glutathione. The addition of recombinant T. denticola cystalysin, an l -cysteine desulfhydrase, to whole cells of A. actinomycetemcomitans resulted in the production of H₂S from glutathione. Subsequently, we cloned A. actinomycetemcomitans GGT gene ( ggt ) and overexpressed the 63 kDa GGT protein. The recombinant A. actinomycetemcomitans GGT was purified and identified. The K _cat/ K _m of the recombinant GGT from N -γ- l -glutamyl-4-nitroaniline as substrate was 31/μ m /min. The activity of GGT was optimum at pH 6.9–7.1 and enhanced by thiol-containing compounds.
Conclusion:  The results demonstrated that A. actinomycetemcomitans had GGT and CGase activities and that the GGT was characterized. The possible role of A. actinomycetemcomitans in glutathione metabolism and H₂S production from oral bacteria was discussed.