三黄片对糖尿病患者血清超氧化物歧化酶及丙二醛的影响

目的 观察三黄片对糖尿病患者血清超氧化物歧化酶(SOD)及丙二醛(MDA)的影响,探讨其抗动脉粥样硬化作用机制.方法 将60例2型糖尿病患者随机分为糖尿病组和三黄片组,糖尿病组在控制血糖及血压的基础上对症治疗,三黄片组在糖尿病组治疗基础上加用三黄片4片,3次/d,口服.根据患者大便情况调整三黄片的用量,使大便保持在1～3次/d.4周后,测定两组患者血清SOD及MDA的变化,并进行比较.结果 三黄片组与糖尿病相比,能明显抑制SOD的降低(P＜0.05),同时能够抑制MDA的升高(P＜0.05).三黄片对糖尿病患者的血糖没有影响.结论 三黄片具有降低糖尿病患者血清MDA及升高SOD的作用,推断其在抗氧化应激层面上具有抗动脉硬化作用.     

Herbal medicines for the prevention of alcoholic liver disease: A review

Ethnopharmacological relevance

Long-term excess alcohol exposure leads to alcoholic liver disease (ALD)—a global health problem without effective therapeutic approach. ALD is increasingly considered as a complex and multifaceted pathological process, involving oxidative stress, inflammation and excessive fatty acid synthesis. Over the past decade, herbal medicines have attracted much attention as potential therapeutic agents in the prevention and treatment of ALD, due to their multiple targets and less toxic side effects. Several herbs, such as Cnidium monnieri (L.) Cusson (Apiaceae), Curcuma longa L. (Zingiberaceae) and Pueraria lobata (Willd.) Ohwi (Leguminosae), etc., have been shown to be quite effective and are being widely used in China today for the treatment of ALD when used alone or in combination.

Aim of the review

To review current available knowledge on herbal medicines used to prevent or treat ALD and their underlying mechanisms.

Materials and methods

We used the pre-set searching syntax and inclusion criteria to retrieve available published literature from PUBMED and Web of Science databases, all herbal medicines and their active compounds tested on ALD induced by both acute and chronic alcohol ingestion were included.

Results

A total of 40 experimental studies involving 34 herbal medicines and (or) active compounds were retrieved and reviewed. We found that all reported extracts and individual compounds from herbal medicines/natural plants could be beneficial to ALD, which might be attributed to regulate multiple critical targets involved in the pathways of oxidation, inflammation and lipid metabolism.

Conclusions

Screening chemical candidate from herbal medicine might be a promising approach to drug discovery for the prevention or treatment of ALD. However, further studies remain to be done on the systematic assessment of herbal medicines against ALD and the underlying mechanisms, as well as their quality control studies.     

NBT光照法测定聚（2-乙基-2-NFDE6唑啉）化超氧化物歧化酶模拟物脂质体的活性

 目的 建立聚（2-乙基-2-NFDE6唑啉）[poly(2-ethyl-2-oxazoline),PEOZ]修饰超氧化物歧化酶（superoxide dismutase,SOD）模拟物脂质体的活性测定方法。方法 以薄膜分散法制备聚（2-乙基-2-NFDE6唑啉）化超氧化物歧化酶模拟物脂质体,利用氮蓝四唑（NBT）光照法对超氧化物歧化酶模拟物及聚（2-乙基-2-NFDE6唑啉）化超氧化物歧化酶模拟物脂质体的活性进行测定。结果 超氧化物歧化酶模拟物的抑制率曲线方程为IR%=33.421lnρ+49.715（r²=0.999 2）,IC₅₀为1.008 6×10^-3 μmol·L^-1;聚（2-乙基-2-NFDE6唑啉）化超氧化物歧化酶模拟物脂质体的抑制率曲线方程IR%=33.521lnρ+49.671（r²=0.999 1）,IC₅₀为1.009 9×10^-3 μmol·L^-1。结论 氮蓝四唑光照法操作简单、稳定可靠、经济实用,可用于超氧化物歧化酶模拟物聚（2-乙基-2-NFDE6唑啉）脂质体的活性测定;经脂质体包裹后超氧化物歧化酶模拟物的活性未发生变化。     

代谢组学在转运蛋白的生物体内功能分析中的应用

转运蛋白是一种允许有机和无机溶质高效率和选择性跨膜透过的膜蛋白。转运蛋白基因的分子识别即通过克隆cDNA外源表达系统的体外实验方法,阐明转运蛋白的功能。代谢组学分析是通过定量比较某化合物在野生型和转运蛋白基因敲除型小鼠的尿液、血液或组织样本的信息,从而揭示生物体内转运蛋白的真正底物。这种方法也可以用来发现孤儿转运蛋白功能。举例说明基于毛细管电泳与质谱联用（CE—MS）技术,应用代谢组学分析,揭示了SLC22转运蛋白家族中一个孤儿转运蛋白的功能。     

Contribution of superoxide to reduced antioxidant activity of glycoxidative serum albumin

Hyperglycemia increases oxidative stress in various tissues and leads to diabetic cardiovascular complication. Dyslipidemia, such as an increase in oxidized low-density lipoprotein (LDL), is well recognized in diabetic patients with hyperglycemia. However, the mechanism by which hyperglycemia causes the increased LDL oxidation remains unclear. Albumin is the most abundant protein in the circulation, and can function as an antioxidant. Therefore, we examined whether glycoxidative modification inhibits the antioxidant activity of albumin to LDL oxidation and clarified the mechanism by which this modification may suppress its antioxidant activity. Human serum albumin (HSA) was incubated in phosphate-buffered saline with and without glucose at 37°C for up to 8 weeks under aerobic conditions (referred to as glycoxidation (goHSA) and oxidation (oHSA), respectively). Metal chelator-treated, nonoxidative HSA (chHSA) and freshly prepared HSA (fHSA) were used as controls. N ^ε-(carboxymethyl)lysine (CML), a glycoxidative product, was determined by enzyme-linked immunosorbent assay. Oxidation was estimated by measuring the thiols of the HSA molecule. Copper-mediated oxidation of LDL was conducted in the presence or absence of modified HSAs at 37°C for 6 days. Malondialdehyde and negative charge of LDL were measured. To clarify the mechanism of reduced antioxidant activity of HSA, we examined firstly the binding activity of modified HSAs to copper, and secondly the effects of free radical scavengers on the formation of malondialdehyde. CML was formed in goHSA in a time- and concentration-dependent manner. Both goHSA and oHSA significantly decreased the contents of free thiol groups compared to ch- and fHSAs. The antioxidant activity of goHSA to LDL oxidation was the lowest among various modified HSAs. The oHSA showed a moderate decrease in antioxidant activity. The binding activity of go- and oHSAs to copper was lower than that of ch- and fHSAs. The formation of MDA from LDL oxidation in the presence of goHSA was completely inhibited by Tiron (1,2-dihydroxy-3,5-benzenedisulfonic acid) and superoxide dismutase. In contrast, catalase and mannitol had no effect. Our results indicate that in vitro glycoxidation of HSA induced a marked loss of antioxidant activity of this molecule to copper-mediated oxidation of LDL, which may be caused by the generation of superoxide. Received: December 17, 2001 / Accepted: June 28, 2002 Acknowledgments The authors thank Drs. Ryoji Nagai and Seikoh Horiuchi (Department of Biochemistry, Kumamoto University School of Medicine, Kumamoto, Japan) and Drs. Hiroyuki Itabe and Tatsuya Takano (Department of Microbiology and Molecular Pathology, Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa, Japan) for kindly supplying antibodies. We also thank Associate Professor Takeo Yamaguchi (Department of Chemistry, Faculty of Science, Fukuoka University) for the ESR experiment and Miss Satoko Nagano for her excellent technical assistance. This work was supported by a Grant-in-Aid from the Ministry of Education, Science, Sports and Culture of Japan (No. 14570171) and in part by funds from the Central Research Institute of Fukuoka University (No. 016004). Correspondence to N. Sakata     

Attenuation of streptozotocin diabetes with superoxide dismutase-like copper(II)(3,5-diisopropylsalicylate)2 in the rat

Summary Experimental diabetes can be produced by agents with specific toxicity for pancreatic islet B cells. This effect has been reported to be modified both in vitro and in vivo by various radical scavengers including the enzyme Superoxide dismutase. Copper(II)(3,5-diisopropylsalicylate)₂ is lipophilic and possesses Superoxide dismutase bioactivity. Prior administration of this compound to male rats appeared to attenuate the severity of streptozotocin-induced diabetes as assessed by glycosuria and glucose tolerance. Diisopropylsalicylate, which has no Superoxide dismutase activity, did not alter the severity of streptozotocin-induced diabetes. Rats treated with the copper complex, with Streptozotocin or with a combination of the two agents gained 50% less weight than untreated controls, or rats treated with diisopropylsalicylate. The attenuation of diabetes by the copper-complex may represent partial protection of the B cells against Streptozotocin damage, although an extrapancreatic, toxic effect cannot be ruled out.     

Preparation and phase transition behaviors of temperature-responsive 3-butoxy-2-hydroxypropyl hydroxyethyl celluloses

2-Hydroxy-3-butoxypropyl hydroxyethyl celluloses (HBPEC), which are thermoresponsive polymers, are prepared by grafting butyl glycidyl ether onto hydroxyethyl cellulose. The effects of several factors on the cloud point (Tc) of the HBPEC are also investigated. The Tc of HBPEC can be tuned to a ranging from 17.0 to 43.0 °C by changing the molar substitution of hydrophobic groups. Increasing the concentration of HBPEC leads to a faster phase transition as well as a corresponding linear decrease in the Tc. A series of salts with common anions or cations are used to investigate the effects of specific anions or cations on the Tc of HBPEC aqueous solutions. It is discovered that the Tc of HBPEC is largely influenced by the variation of cation identity and concentration. Plotting Tc as a function of cation activity shows that the Tc can be classified by charge density.     

The Complement—Fixing Activity of Immune Complexes Containing IgG Antibodies of Different Functional Affinities: Effects on Superoxide Production by Rabbit Neutrophils

When neutrophil phagocytes are stimulated by IgG containing immune complexes (IgG‐IC), with or without the participation of the complement system, they show a sharp increase in oxygen uptake and begin to release large quantities of superoxide anions (O₂^?) and hydrogen peroxide (H₂O₂) into the surrounding medium. The aim of the present investigation was to provide insights into the production and release of O₂^? by rabbit neutrophils activated with immune complexes (IC) containing IgG antibodies of different functional affinity, opsonized and not opsonized by complement system components. For this purpose, two populations of polyclonal anti‐ovalbumin (OVA) IgG antibodies with different functional affinity, 5 × 10⁸ M^{? 1} and 2 × 10⁷ M^{? 1}, were prepared. The production of O₂^? was measured spectrophotometrically by a method using the superoxide dismutase‐inhibited reduction of ferricytochrome C to the ferrous form. The activation of complement by different IgG‐IC was determined by estimating the total residual haemolytic activity of the alternative and classical pathways in sera treated with different concentrations of anti‐OVA IgG/OVA immune complexes formed at equivalence. The results showed that: 1) antibody functional affinity influenced O₂^? production and the complement‐fixing activity induced by the IC. In general, the higher functional affinity antibodies were more efficient in stimulating the respiratory burst of neutrophils and in activating complement by the classical and alternative pathways than the lower functional affinity antibodies at all IC concentrations tested; 2) complement components incorporated into the immune complex lattice caused an increase in the stimulatory activity of both IgG antibodies to produce O₂^? (? 15% for the IC of IgG with K_a = 5 × 10⁸ M^{? 1} and ? 7% for the IC of IgG with K_a = 2 × 10⁷ M^{? 1}). This effect was dependent on antibody affinity and concentration; 3) there was a direct relationship between the overall level of complement activation, antibody affinity and superoxide production by neutrophils. Thus, we conclude that antibody affinity influences immune complex lattice formation, modulating its three‐dimensional structure and the disposition of Fc fragments interfering with the antibody's biological properties. These results can help understand the precise role of antibody functional affinity in antigen‐antibody complex diseases and define the immunochemical characteristics of pathogenic complexes.     

A mitochondrial superoxide theory for oxidative stress diseases and aging

Fridovich identified CuZnSOD in 1969 and manganese superoxide dismutase (MnSOD) in 1973, and proposed ”the Superoxide Theory,” which postulates that superoxide (O₂^•−) is the origin of most reactive oxygen species (ROS) and that it undergoes a chain reaction in a cell, playing a central role in the ROS producing system. Increased oxidative stress on an organism causes damage to cells, the smallest constituent unit of an organism, which can lead to the onset of a variety of chronic diseases, such as Alzheimer’s, Parkinson’s, amyotrophic lateral sclerosis and other neurological diseases caused by abnormalities in biological defenses or increased intracellular reactive oxygen levels. Oxidative stress also plays a role in aging. Antioxidant systems, including non-enzyme low-molecular-weight antioxidants (such as, vitamins A, C and E, polyphenols, glutathione, and coenzyme Q₁₀) and antioxidant enzymes, fight against oxidants in cells. Superoxide is considered to be a major factor in oxidant toxicity, and mitochondrial MnSOD enzymes constitute an essential defense against superoxide. Mitochondria are the major source of superoxide. The reaction of superoxide generated from mitochondria with nitric oxide is faster than SOD catalyzed reaction, and produces peroxynitrite. Thus, based on research conducted after Fridovich’s seminal studies, we now propose a modified superoxide theory; i.e., superoxide is the origin of reactive oxygen and nitrogen species (RONS) and, as such, causes various redox related diseases and aging.     

Manganese superoxide dismutase activity and incidence of hepatocellular carcinoma in patients with Child-Pugh class A liver cirrhosis: a 7-year follow-up study.

AIMS: To evaluate possible modifications in the manganese superoxide dismutase (MnSOD) activity during neoplastic transformation of a cirrhotic liver and to find out whether its assessment may have predictive value to identify cirrhotic patients at a higher risk of hepatocellular carcinoma (HCC). METHODS: Seventy-one consecutive subjects with Child-Pugh class A liver cirrhosis were recruited. At the time of enrolment, HCC was diagnosed in 20 cirrhotic patients. The 51 cirrhotic patients without HCC were followed up for the occurrence of tumour by 6-monthly screening for 7 years. During follow-up, 16 patients developed HCC. Seventy healthy subjects formed the control group. MnSOD activity was assayed spectrophotometrically. RESULTS: Serum MnSOD activity was significantly lower in 70 healthy subjects compared with 51 cirrhotic patients and 20 cirrhotic patients with HCC. Cirrhotic patients who developed HCC during follow-up showed significantly higher values of MnSOD activity than HCC-free patients. The best cut-off of MnSOD activity was 0.40 U/ml. At this cut-off, chi2 analysis revealed that MnSOD activity was significantly different between the HCC-free cirrhotic patients and cirrhotic patients who developed HCC. CONCLUSION: The present findings suggest that during neoplastic transformation of cirrhotic liver, an increase in MnSOD activity may occur already during the precancerous phase, making this enzyme a probable malignancy-associated parameter.