Molecular Mechanism and Molecular Design of Lubricating Oil Antioxidants

To overcome the limitations of traditional experimental“trial and error”methods in lubricant additive design,a new molecular design method based on molecular structure parameters is established here.The molecular mechanism of the antioxidant reaction of hindered phenol,diphenylamine,and alkyl sulfide are studied via molecular simulations.Calculation results show that the strong electron-donating ability and high hydrogen-donating activity of the antioxidant molecule and the low hydrogen-abstracting activity of free radicals formed after dehydrogenation are the internal molecular causes of the shielding of phenol and diphenylamine from scavenging peroxy free radicals,and the strong electron-donating ability is the internal molecular cause of the high activity of thioether in decomposing alkyl hydrogen peroxide.Based on this antioxidant molecular mechanism,a molecular design rule of antioxidant is proposed,namely“high EHOMO,large Q(S),low bond dissociation energy BDE(O—H)and BDE(N—H)”.Two new antioxidants,PAS-I and PAS-II,are designed and prepared by chemical bonding of hindered phenol,diphenylamine,and sulfur atoms.Experimental results show that these antioxidants both have excellent antioxidant effects in lubricating oil,and that PAS-II is the superior antioxidant,consistent with theoretical predictions.

Effect of antioxidants on the efficiency of jet milling and the powder characteristics of Sm2Co17 permanent magnets

This study investigated the effect of antioxidants on the grinding efficiency,magnetic powder characteristics,microstructure,and magnetic properties of 2:17 type SmCo permanent magnet materials.The results show that adding antioxidants helps improve the dispersion among magnetic powders,leading to a 33.3%decrease in jet milling time and a 15.8%increase in magnet powder production yield.Additionally,adding antioxidants enhances the oxidation resistance of the magnetic powders.After being stored in a constant temperature air environment at 25C for 48 h,the O content in the powder decreased by 33%compared to samples without antioxidants.While in the magnet body,the O content decreased from 0.21 wt.%to 0.14 wt.%,which helps increase the effective Sm content and domain wall pinning uniformity in the magnet.Excellent magnetic properties were obtained in the magnet with added antioxidants:B_(r)=11.6 kGs,SF=79.6%,H_(cj)=16.8 kOe,and(BH)_(max)=32.5 MGOe.

Distribution of antioxidants and phenolic compounds in flour milling fractions from hard red winter wheat

Mature wheat kernels contain three main parts:endosperm,bran,and germ.Flour milling results in multiple streams that are chemically different;however,the distribution of antioxidants and phenolic compounds has not been well documented in terms of conventional milling by-product streams.In this study,multiple analytical methods were used to investigate antioxidant activity and phenolic compound compositions of hard red winter wheat(whole ground wheat),the parts of a wheat kernel(bran,flour,germ),and wheat by-product streams(mill feed,red dog,shorts)for the first time.For each mill stream,phenolic compounds(total,flavonoid,and anthocyanin contents)were determined and antioxidant activities were evaluated with 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical-scavenging activity,ferric reducing/antioxidant power(FRAP),and total antioxidant capacity assays.Significant differences(P<0.05)were observed in phenolic concentrations among fractions of bran,flour,and germ milled from the same kernels and noted that germ accounts for the majority of antioxidant properties,whereas bran contains a substantial portion of phenolic compounds and anthocyanins.Mill feed was high in phenolic content(5.29 mg FAE/g),total antioxidant capacity(866 mg/g),and antioxidant activity(up to 75% DPPH inhibition and 20.26μmol FeSO_(4)/g).The comprehensive information on distribution of antioxidants and phenolic compounds provides insights for future human consumption of commonly produced co-products from flour milling,and for selecting and using different milling fractions to make foods with improved nutritional properties.

钛表面多酚介导铜离子涂层制备及抗菌抗氧化性能

背景:钛植入体因比强度高及良好的生物相容性被广泛应用于临床,然而在植入手术过程中,细菌感染及组织受损环境产生大量活性氧物质易导致组织延迟愈合与手术失败,因此开发具有抗菌和抗氧化性能的钛植入体极为重要。目的:鉴于铜离子良好的抗菌性能及多酚类物质优良的抗氧化性能,拟在钛表面制备多酚介导的铜离子涂层,评价其体外抗菌及抗氧化性能。方法:利用碱热法在钛表面制备纳米结构,然后将钛片置于单宁酸及铜离子溶液中,获得多酚介导的铜离子涂层,检测样品的表面形貌与水接触角,利用原子吸收光谱法检测铜离子的携载及释放。将金黄色葡萄球菌分别接种于纯钛片(空白组)、碱热处理钛片(对照组)、多酚介导的铜离子修饰钛片(实验组)表面,观察细菌存活状态。将成骨前体细胞MC3T3-E1分别接种于3组钛片表面,评价材料的抗氧化性能及生物活性。结果与结论:(1)扫描电镜下可见多酚介导的铜离子修饰钛片表面存在棒状纳米结构,并且涂层无裂纹;多酚介导的铜离子修饰钛片表面亲水性接近纯钛片;原子吸收光谱结果显示,多酚介导后钛片表面铜离子的携载量增加了51%,铜离子呈均匀释放。(2)空白组、对照组、实验组钛片的抗菌率为0%,21.65%,93.75%;活死染色与CTC染色显示,空白组钛片表面的活细菌最多,实验组钛片表面的活细菌最少。(3)活死染色与CCK-8检测结果显示,3组钛片均具有良好的细胞相容性,并且实验组钛片更有利于MC3T3-E1细胞增殖;活性氧荧光探针检测显示,相较于其他两组,实验组钛片表面活性氧荧光强度明显减弱;碱性磷酸酶与茜素红S染色结果显示,相较于其他两组,实验组钛片表面MC3T3-E1细胞的成骨分化与细胞外基质矿化能力更强。(4)结果表明,多酚介导的铜离子涂层具有较强的抗菌、抗氧化及促成骨分化性能。

PHENOLIC ANTIOXIDANTS DETERMINATION IN FOOD ITEMS USING REVERSED-PHASE HPLC

The determination of synthetic phenolic antioxidants （SPAs） including propyl gallate （PG）, tertiary butyl hydroquinone （TI3HQ）, butylated hydroxyanisole （BHA） and butylated hydroxytoluene （BHT） in food items is reported using high performance liquid chromatography （HPLC）. A Cls column is used as the stationary phase, acetonltrile and water：Acetic acid （1%） is used as the mobile phase of gradient elution and the UV detec- tor is set at 280 nm. Under the above conditions, four antioxidents is completely separated within 8 rain. The limit of detection, linear range, and reproducibility of HPLC are evaluated. Isolation parameters of SPAs from different types of food items （cooking oil, margarine and butter, and cheese） are optimized. SPAs are extracted from food items through extraction with methanol/acetonitrile （1 ： 1, in volume）, vortex, ultrasonic treatment and precipitation in a freezer （2 h）. For cooking oil margarine, butter and cheese at 50 and 200 rag/L, recoveries of SPAs are 93.3%0--108.3% （PG）, 85.3~^--108.3~~ （TBHQ）, 96.7~^--101.2~/6 （BHA）, and 73.9^-- 94.6% （BHT）. The method is applied to the determination of SPAs in 38 food items （16 cooking oils, 8 mar- garine, 6 butter and 6 cheese samples）. The levels of SPAs in positive samples are all below the legal limits of China.

多维度定性定量评价电子束辐照灭菌对黄芪质量的影响

为探究电子束辐照灭菌对黄芪质量的影响,采用不同辐照吸收剂量(2、4、6、8、10、12、14、16、18 kGy)处理黄芪样品,测定其微生物水平、多种化学成分含量、抗氧化活性及大鼠肝星状细胞(HSC-T6)的细胞存活率,比较灭菌前后表面增强拉曼光谱(SERS)指纹图谱及高效液相色谱(HPLC)指纹图谱。结果表明,吸收剂量≥10 kGy时,黄芪微生物水平符合《中华人民共和国药典2020年版四部》规定;不同吸收剂量下黄芪中毛蕊异黄酮含量、毛蕊异黄酮苷含量、刺芒柄花素含量、芒柄花苷含量、2,2-联苯基-1-苦基肼基自由基(DPPH·)清除率、3-氧代-2苯基-4,4,5,5-四甲基咪唑啉-1氧自由基(PTIO·)清除率、铁氰化钾还原力及大鼠肝星状细胞(HSC-T6)存活率较灭菌前均无显著差异(P>0.05);灭菌后黄芪SERS指纹图谱、HPLC指纹图谱与未灭菌样品图谱相比,相似度均大于0.900;液相色谱-质谱联用(LC-MS)确认HPLC指纹图谱中13个共有峰结构,灰色关联度分析显示13个共有峰与抗氧化活性关联度均大于0.600,毛蕊异黄酮、毛蕊异黄酮苷、刺芒柄花素、芒柄花苷含量与黄芪抗氧化活性的关联度均大于0.700。综上,吸收剂量18 kGy及以下的电子束辐照灭菌对黄芪质量无影响,上述4种化合物含量与黄芪抗氧化性具有较强的相关性,可作为其抗氧化活性的质量标志物。本研究可为电子束灭菌技术在黄芪灭菌加工中的应用提供理论依据和技术支持。

DFT Study on Molecular Structures and ROS Scavenging Mechanisms of Novel Antioxidants from Lespedeza Virgata

The molecular structure and radical scavenging activity of three novel antioxidants from Lespedeza Virgata, lespedezavirgatol, lespedezavirgatal, and lespedezacoumestan, have been studied using density functional theory with the B3LYP and BhandHLYP methods. The optimized geometries of neutral, radical cation, radical and anion forms were obtained at the B3LYP/6-31G（d） level, in which it was found that all the most stable conformations contain intramolecular hydrogen bonds. The same results were obtained from the MP2 method. The homolytic O-H bond dissociation enthalpy and the adiabatic ionization potential of neutral and anion forms for the three new antioxidants and adiabatic electron affinity and H-atom affinity for hydroxyl radical, superoxide anion radical, and hydrogen peroxide radical were determined both in gas phase and in aqueous solution using IEF-PCM and CPCM model with UAHF or Bondi cavity. The antioxidant activities and reactive oxygen species scavenging mechanisms were then discussed, and the results obtained from different methods are consistent. Furthermore, the antioxidant activities are consistent with the experimental findings of the compounds under investigation.

铁死亡与周围神经损伤的关系

背景:研究已证实铁死亡与多种神经系统疾病的发生机制密切相关,但铁死亡和周围神经损伤后的病理生理机制有待进一步研究和阐明。目的:综述细胞铁死亡在治疗周围神经损伤进程中的相关作用与作用机制。方法:检索CNKI、PubMed等数据库建库至2024年5月期间铁死亡与周围神经系统损伤的相关文献,检索词为“ferroptosis,Peripheral nerve injury,Antioxidant defense system,Schwann cells,Macrophage,Neuroinflammation,Neuropathic pain”和“铁死亡,周围神经损伤,抗氧化防御系统,施万细胞,巨噬细胞,神经炎症,神经性疼痛”,最终纳入60篇文献进行分析。结果与结论:铁死亡的发生与细胞内铁代谢异常、活性氧积累及脂质过氧化密切相关。周围神经损伤后施万细胞和巨噬细胞均发生铁死亡,导致微环境变化,并且进一步诱导神经炎症及神经疼痛等疾病的发生。越来越多的研究表明神经损伤与铁死亡密切相关,抑制铁死亡可以促进周围神经损伤后的组织修复及功能恢复,因此,研究周围神经损伤细胞铁死亡的发生机制及调节有着重要意义。目前对铁死亡与周围神经损伤后的作用和调控研究仍处于起步阶段,需要进行更深入的研究,为促进周围神经损伤后修复提供更多的策略。

Nanoparticles for the treatment of spinal cord injury

Spinal cord injuries lead to significant loss of motor, sensory, and autonomic functions, presenting major challenges in neural regeneration. Achieving effective therapeutic concentrations at injury sites has been a slow process, partly due to the difficulty of delivering drugs effectively. Nanoparticles, with their targeted delivery capabilities, biocompatibility, and enhanced bioavailability over conventional drugs, are garnering attention for spinal cord injury treatment. This review explores the current mechanisms and shortcomings of existing treatments, highlighting the benefits and progress of nanoparticle-based approaches. We detail nanoparticle delivery methods for spinal cord injury, including local and intravenous injections, oral delivery, and biomaterial-assisted implantation, alongside strategies such as drug loading and surface modification. The discussion extends to how nanoparticles aid in reducing oxidative stress, dampening inflammation, fostering neural regeneration, and promoting angiogenesis. We summarize the use of various types of nanoparticles for treating spinal cord injuries, including metallic, polymeric, protein-based, inorganic non-metallic, and lipid nanoparticles. We also discuss the challenges faced, such as biosafety, effectiveness in humans, precise dosage control, standardization of production and characterization, immune responses, and targeted delivery in vivo. Additionally, we explore future directions, such as improving biosafety, standardizing manufacturing and characterization processes, and advancing human trials. Nanoparticles have shown considerable progress in targeted delivery and enhancing treatment efficacy for spinal cord injuries, presenting significant potential for clinical use and drug development.

载富血小板血浆水凝胶对L929细胞氧化损伤的保护作用

背景:在慢性创面愈合过程中,活性氧的过量生成可能会损害L929成纤维细胞的功能,从而延缓创面修复,因此保护成纤维细胞免受氧化应激的影响对于促进创面愈合非常重要。目的:评估羧甲基壳聚糖-氧化硫酸软骨素/富血小板血浆(CMC-OCS/PRP)水凝胶对H2O2刺激下L929细胞的保护作用。方法:制备CMC-OCS/PRP水凝胶,表征水凝胶的微观形貌、降解性能、清除H2O2与羟基自由基的能力及生物相容性。取生长状态良好的L929细胞,分5组培养:对照组常规培养,H2O2组加入H2O2,CMC-OCS组加入羧甲基壳聚糖-氧化硫酸软骨素水凝胶浸提液+H2O2,PRP组加入富血小板血浆凝胶浸提液+H2O2,CMC-OCS/PRP组加入羧甲基壳聚糖-氧化硫酸软骨素/富血小板血浆水凝胶浸提液处理+H2O2,每组先加入水凝胶浸提液处理6 h,然后再加入H2O2处理24 h。培养结束后,检测细胞活性氧及丙二醛水平,细胞凋亡、胶原纤维Ⅰ蛋白表达。在加入H2O2的情况下,将上述水凝胶浸提液分别与L929成纤维细胞直接或间接共培养36 h,通过划痕实验、Transwell小室实验检测细胞的迁移能力。结果与结论:①CMC-OCS/PRP水凝胶具有均匀相互关联的多孔结构及良好的降解能力,体外可有效清除H2O2与羟基自由基,并且具有良好的生物相容性;②与对照组比较,H2O2组细胞凋亡率、细胞活性氧与丙二醛水平升高(P<0.05),细胞铺展面积减少(P<0.05),胶原纤维Ⅰ蛋白表达无明显变化(P>0.05);与H2O2组比较,CMC-OCS组、CMC-OCS/PRP组细胞活性氧水平降低(P<0.05),PRP组、CMC-OCS组、CMCOCS/PRP组丙二醛水平降低(P<0.05)、细胞铺展面积增加(P<0.05),CMC-OCS/PRP组细胞凋亡率降低(P<0.05),PRP组、CMC-OCS组、CMCOCS/PRP组胶原纤维Ⅰ蛋白表达增加(P<0.05);③与对照组比较,H2O2组细胞迁移数量减少(P<0.05),迁移面积无明显变化(P>0.05);与H2O2组比较,PRP组、CMC-OCS组、CMC-OCS/PRP组细胞迁移数量、迁移面积均增加(P<0.05),并且以CMC-OCS/PRP组增加最显著;④在氧化应激条件下,CMC-OCS/PRP水凝胶可改善成纤维细胞的迁移能力,抗细胞凋亡并保护细胞伸展功能。

Phytochemical analysis and antioxidants activities of aqueous stem bark extract of Schotia latifolia Jacq

Objective:To evaluate the phytochemical constituents and antioxidant activities of aqueous extract of Scholia latifolia(S.latifolia)bark locally used for the treatment of oxidative stress-induced ailments in South Africa.Methods:The antioxidant and free radical scavenging activity of aqueous extract of the plant was assessed against 1,1-diphenyl-2-pierylhydrazyl(DPPH),nitric oxide(NO),2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt(ABTS)and the ferric reducing agent.Total phenolics,flavonoids,flavonols and proanthocyanidins were also determined to assess their corresponding effect on the antioxidant activity of this plant.Results:The activities of plant extract against DPPH,ABTS and NO radicals were concentration dependent with IC_(50)value of 0.06,0.05 and 0.05 mg/mL,respectively.The reducing power of the extract was greater than that of butylated hydroxyl toluene(BHT)and ascorbic acid which were used as standard drugs in a concentration dependent manner.The total phenolics content of the aqueous bark extract was(193.33±0.03 TE/g),followed by flavonoids(72.70±0.01 QE/g),proanthocyanidins|48.76±0.00 CE/g)and flavonols(47.76±0.21 QE/g).Phytochemical analysis revealed the presence of percentage tannin(11.40±0.02),alkaloid(9.80±0.01),steroids(18.20±0.01),glycosides(29.80±0.01)and saponins(6.80±0.00).The results exhibited a positive linear correlation between these polyphenols and the free radical scavenging activities.Conclusions:Our findings provide evidence that the crude aqueous extract of S.latifolia is a potential source of natural antioxidants and this justifies its uses in folkloric medicines.

Relationships among alcoholic liver disease,antioxidants,and antioxidant enzymes

Excessive consumption of alcoholic beverages is a serious cause of liver disease worldwide.The metabolism of ethanol generates reactive oxygen species,which play a significant role in the deterio-ration of alcoholic liver disease(ALD).Antioxidant phytochemicals,such as polyphenols,regulate the expression of ALD-associated proteins and peptides,namely,catalase,superoxide dismutase,glutathione,glutathione peroxidase,and glutathione reductase.These plant antioxidants have electrophilic activity and may induce antioxidant enzymes via the Kelch-like ECH-associated protein 1--NF--E2--related factor--2 pathway and antioxidant responsive elements.Furthermore,these antioxidants are reported to alleviate cell injury caused by oxidants or inflammatory cytokines.These phenomena are likely induced via the regulation of mitogen--activating protein kinase(MAPK)pathways by plant antioxidants,similar to preconditioning in ischemia-reperfusion models.Although the relationship between plant antioxidants and ALD has not been adequately investigated,plant antioxidants may be preventive for ALD because of their electrophilic and regulatory activities in the MAPK pathway.

The research and development on the antioxidants in prevention of diabetic complications

Diabetes mellitus can damage the eyes,kidneys,nerves and heart.Microvascular and macrovascular disorders are the leading causes of morbidity and mortality in diabetic patients.Hyperglycemia can increase the indicators of lipid peroxidation and oxidative stress in which free radicals have the main role in the pathogenesis of these complications.Therefore,antioxidants which combat oxidative stress should be able to prevent and repair free radicals induced damages.Although free radicals contribute to kidney damage,atherosclerosis,diabetes,heart disease,nephrotoxicity and hepatotoxicity; however,clinical trials do not uniquely confirm a substantial impact on diabetic damage.It seems that antioxidants in vegetables,fruits and grains help preventing diabetes complications; however,there is little evidence that taking single antioxidants such as vitamin E or vitamin C protect these complications.The findings about combination antioxidants are also complicated and not entirely clear.In this review paper we tried to present the role of oxidative stress on microvascular complications of type2 diabetes mellitus.Other objective of this paper is to review the new findings about the role of various antioxidants on prevention and treatment of diabetes mellitus as well as its complications including retinopathy,nephropathy and neuropathy.

Oxidative stress and antioxidants in hepatic pathogenesis

Long term hepatitis B virus (HBV) infection is a major risk factor in pathogenesis of chronic liver diseases,including hepatocellular carcinoma (HCC). The HBV encod-ed proteins,hepatitis B virus X protein and preS,appear to contribute importantly to the pathogenesis of HCC. Both are associated with oxidative stress,which can damage cellular molecules like lipids,proteins,and DNA during chronic infection. Chronic alcohol use is another important factor that contributes to oxidative stress in the liver. Previous studies reported that treatment with antioxidants,such as curcumin,silymarin,green tea,and vitamins C and E,can protect DNA from damage and regulate liver pathogenesis-related cascades by reducing reactive oxygen species. This review summarizes some of the relationships between oxidative stress and liver pathogenesis,focusing upon HBV and alcohol,and suggests antioxidant therapeutic approaches.

Relationship of nocturnal concentrations of melatonin, gamma-aminobutyric acid and total antioxidants in peripheral blood with insomnia after stroke： study protocol for a prospective non-randomized controlled trial

Melatonin and gamma-aminobutyric acid（GABA） have been shown to regulate sleep. The nocturnal concentrations of melatonin, GABA and total antioxidants may relate to insomnia in stroke patients. In this prospective single-center non-randomized controlled clinical trial performed in the China Rehabilitation Research Center, we analyzed the relationship of nocturnal concentrations of melatonin, GABA and total antioxidants with insomnia after stroke. Patients during rehabilitation of stroke were recruited and assigned to the insomnia group or non-insomnia group. Simultaneously, persons without stroke or insomnia served as normal controls. Each group contained 25 cases. The primary outcome was nocturnal concentrations of melatonin, GABA and total antioxidants in peripheral blood. The secondary outcomes were Pittsburgh Sleep Quality Index, Insomnia Severity Index, Epworth Sleepiness Scale, Fatigue Severity Scale, Morningness-Eveningness Questionnaire（Chinese version）, and National Institute of Health Stroke Scale. The relationship of nocturnal concentrations of melatonin, GABA and total antioxidants with insomnia after stroke was analyzed and showed that they were lower in the insomnia group than in the non-insomnia group. The severity of stroke was higher in the insomnia group than in the non-insomnia group. Correlation analysis demonstrated that the nocturnal concentrations of melatonin and GABA were associated with insomnia after stroke. This trial was registered at Clinical Trials.gov, identifier： NCT03202121.

干细胞抗卵巢颗粒细胞衰老的作用机制及进展

背景:干细胞疗法作为一种新兴的治疗手段,有望改善卵巢环境,延缓卵巢颗粒细胞的衰老,为高龄妊娠女性带来新的希望。目的:综述干细胞抗卵巢颗粒细胞衰老的机制及研究进展。方法:检索中国知网和PubMed数据库中关于干细胞抗卵巢颗粒细胞衰老的文献,以“干细胞,卵巢颗粒细胞,衰老”为中文检索词,以“stem cells,ovary granulosa cells,aging”为英文检索词,最终纳入67篇文献进行分析。结果与结论:①总结了5种卵巢颗粒细胞衰老的机制:DNA损伤和修复能力下降、氧化应激、线粒体功能受损、炎症反应、激素水平变化;②整理了当前干细胞治疗卵巢颗粒细胞衰老的5种机制:促进增殖和抑制凋亡、分化潜能及再生能力、分泌因子、抗氧化、抗炎症反应和免疫调节;③目前有多种类型的干细胞可通过多种方式协同治疗卵巢颗粒细胞衰老,干细胞疗法在恢复女性生育能力方面具有广阔前景。

Evaluation of anti-apoptotic activity of different dietary antioxidants in renal cell carcinoma against hydrogen peroxide

Objective:To evaluate the anti-apoptotic and radical scavenging activities of dietary phenolics, namely ascorbic acid,a-tocopherol acetate,citric acid,salicylic acid,and estimate H_2O_2induced apoptosis in renal cell carcinoma cells.Methods:The intracellular antioxidant potency of antioxidants was investigated.H_2O-2-induced apoptosis in RCC-26 was assayed with the following parameters:cell viability(%apoptosis),nucleosomal damage and DNA fragmentation, bcl-2 levels and flow cytometery analysis(ROS production evaluation).Results:Ine anticancer properties of antioxidants such as ascorbic acid,a- tocopherol acetate,citric acid,salicylic acid with perdurable responses were investigated.It was observed that these antioxidants had protective effect(anti-apoptotic activity) against hydrogen peroxide(H_2O_2) in renal cell carcinoma(RCC-26) cell line.Conclusions:This study reveals and proves the anticancer properties.However,in cancer cell lines anti-apoptotic activity can indirectly reflect the cancer promoter activity through radicals scavenging,and significantly protect nucleus and bcl-2.

Effect of Commiphora mukul gum resin on hepatic marker enzymes,lipid peroxidation and antioxidants status in pancreas and heart of streptozotocin induced diabetic rats

Objective:To study the antioxidant efficacy of Commiphora mukul(C.mukul) gum resin ethanolic extract in streptozotocin(STZ) induced diabetic rats.Methods:The male Wistar albino rats were randomly divided into four groups of eight animals each:Control group(C),CM-treated control group(C_+CMEE),Diabetic control group(D),CM- treated diabetic group(D_+CMEE).Diabetes was induced by intraperitoneal injection of STZ(55 mg/kg/ bwt).After being confirmed the diabetic rats were treated with C.mukul gum resin ethanolic extract(CMEE) for 60 days.The biochemical estimations like antioxidant,oxidative stress marker enzymes and hepatic marker enzymes of tissues were performed.Results:The diabetic rats showed increased level of enzymatic activities aspartate aminotransaminase(AST),alanine aminotransaminase(ALT) in liver and kidney and oxidative markers like lipid peroxidation(LPO) and protein oxidation(PO) in pancreas and heart. Antioxidant enzyme activities were significantly decreased in the pancreas and heart compared to control group.Administration of CMEE(200 mg/kg bw) to diabetic rats for 60 days significantly reversed the above parameters towards normalcy.Conclusions:In conclusion,our data indicate the preventive role of C.mukul against STZ-induced diabetic oxidative stress;hence this plant could be used as an adjuvant therapy for the prevention and/or management of diabetes and aggravated antioxidant status.

Matrix metalloproteinases and gastrointestinal cancers: Impacts of dietary antioxidants

The process of carcinogenesis is tightly regulated by antioxidant enzymes and matrix degrading enzymes, namely, matrix metalloproteinases(MMPs). Degradation of extracellular matrix(ECM) proteins like collagen, proteoglycan, laminin, elastin and fibronectin is considered to be the prerequisite for tumor invasion and metastasis. MMPs can degrade essentially all of the ECM components and, most MMPs also substantially contribute to angiogenesis, differentiation, proliferation and apoptosis. Hence, MMPs are important regulators of tumor growth both at the primary site and in distant metastases; thus the enzymes are considered as important targets for cancer therapy. The implications of MMPs in cancers are no longer mysterious; however, the mechanism of action is yet to be explained. Herein, our major interest is to clarify how MMPs are tied up with gastrointestinal cancers. Gastrointestinal cancer is a variety of cancer types, including the cancers of gastrointestinal tract and organs, i.e., esophagus, stomach, biliary system, pancreas, small intestine, large intestine, rectum and anus. The activity of MMPs is regulated by its endogenous inhibitor tissue inhibitor of metallopro-teinase(TIMP) which bind MMPs with a 1:1 stoichiometry. In addition, RECK(reversion including cysteinerich protein with kazal motifs) is a membrane bound glycoprotein that inhibits MMP-2,-9 and-14. Moreover, α2-macroglobulin mediates the uptake of several MMPs thereby inhibit their activity. Cancerous conditions increase intrinsic reactive oxygen species(ROS) through mitochondrial dysfunction leading to altered protease/anti-protease balance. ROS, an index of oxidative stress is also involved in tumorigenesis by activation of different MAP kinase pathways including MMP induction. Oxidative stress is involved in cancer by changing the activity and expression of regulatory proteins especially MMPs. Epidemiological studies have shown that high intake of fruits that rich in antioxidants is associated with a lower cancer incidence. Evidence indicates that some antioxidants inhibit the growth of malignant cells by inducing apoptosis and inhibiting the activity of MMPs. This review is discussed in six subchapters, as follows.

Hepatoprotective effects of antioxidants in chronic hepatitis C

We have read with interest the paper published in issue 2, volume 16 of World Journal of Gastroenterology 2010 by Nakamura et al, demonstrating that the antioxidant resveratrol (RVT) enhances hepatitis C virus (HCV) replication, consequently, they conclude that RVT is not a suitable antioxidant therapy for HCV chronic infection. The data raise some concern regarding the use of complementary and alternative medicine since the most frequent supplements taken by these patients are antioxidants or agents that may be beneficial for different chronic liver diseases. A recent study by Vidali et al on oxidative stress and steatosis in the progression of chronic hepatitis C concludes that oxidative stress and insulin resistance contribute to steatosis, thus accelerating the progression of fibrosis. We are particularly interested in investigating how the oxidative and nitrosative stress mechanisms are involved in the pathogenesis of different chronic liver diseases.