芦丁-锗配合物及其自由基清除活性研究

芦丁是存在于多种植物中的天然多羟基黄酮苷,能与多种金属离子形成配合物。本文采用紫外分光度法考察了芦丁与锗离子的配位作用,并研究了芦丁-锗配合物清除超氧自由基和DPPH自由基的作用。结果显示在KH2PO4-NaOH(pH6．70)的缓冲液中,芦丁与锗离子能形成1：1的配合物,其K稳=10^7.46,同时配合物显示有较好的自由基清除活性。     

灵芝抗氧化清除自由基作用的研究

文中综述了灵芝的抗氧化清除自由基作用。灵芝对各种因素引起的脑、心脏、胰腺、肝脏、胃肠道、肾脏和其他重要脏器的脂质过氧化损伤具有明显的保护作用。灵芝可显著减少脂质过氧化产物丙二醛(MDA)的含量,增强抗氧化酶如超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)以及其他抗氧化酶的活性。稹灵芝对体外培养的巨噬细胞(小鼠)、胰岛细胞(小鼠)、大脑皮层细胞(大鼠)、嗜铬细胞瘤细胞(大鼠)、血管内皮细胞(大鼠、人)和皮肤角质细胞(人)的氧化损伤具有明显保护作用。灵芝在体内外对不同动物模型和细胞模型的抗氧化清除自由基作用可能与其免疫调节、抗肿瘤、降血压、降血糖、保肝、心血管保护和抗衰老作用的机制有关。     

Free Radical Scavenging Properties of Sulfinpyrazone

Sulfinpyrazone, a potent uricosuric drug, was tested in vitro for its scavenging action against oxygen free radicals. In this study, sulfinpyrazone was able to scavenge 1,1-diphenyl-2-picrylhydrazyl radical with IC 50 value of 29.82 &#119 g/ml compared to butylated hydroxytoluene (BHT, IC 50 value=20.15 &#119 g/ml) and Trolox (IC 50 value=16.01 &#119 g/ml). It was able to scavenge superoxide anion with IC 50 value of 27.72 &#119 g/ml compared to Trolox (IC 50 value=22.08 &#119 g/ml) and ascorbic acid (IC 50 value=14.65 &#119 g/ml). The hydroxyl radical scavenging activity of sulfinpyrazone is in a concentration-dependent fashion. In the range of concentrations used, sulfinpyrazone was not a scavenger toward H 2 O 2 . However, the intracellular H 2 O 2 -induced 2',7'-dichlorofluorescin diacetate (DCF-DA) fluorescence in HL-60 cells was significantly reduced by sulfinpyrazone during 30-60 min of incubation. Finally, phorbol-12-myristate-13-acetate induced-lucigenin chemiluminescence in whole blood was markedly inhibited by sulfinpyrazone. Our results suggest a new direction for the pharmacological actions of sulfinpyrazone in free radical scavenging properties.     

An Organoselenium Drug with Antioxidant Activity and Free Radical Scavenging Capacity In Vitro

Organoselenum compounds have been reported to have a wide range of pharmacological properties. Amine-based diselenide, (Z)-N-(4-methylbenzylidene)-1-(2-((2-(1-((E)-4-methyl benzylideneamino)ethyl)phenyl)diselanyl)phenyl)ethanamine ethyl)phenyl) diselanyl) phenyl) ethylimino) methyl)phenol (compound A), and diphenyl diselenide (PhSe)2 were screened for in vitro antioxidant activity. Compound A and (PhSe)2 were tested against sodium nitroprusside (SNP)- and Fe(II)-induced thiobarbituric acid-reactive species (TBARS) in rat brain homogenates. The radical scavenging activity was measured by 1,1-diphenyl-2-picrylhydrazyl assay. Both compounds A and (PhSe)2 decreased Fe(II)- and SNP-stimulated TBARS production in rat brain homogenates. Compound A exhibited the strongest antioxidant activity in the radical scavenging assay, although (PhSe)2, the simplest of the diaryl diselenide, presented no activity. In conclusion, the results of the present investigation indicated that compound A and (PhSe)2 had preventive effects against SNP- and Fe(II)-induced oxidative stress in rat brain homogenates. The amine group in the organic moiety dramatically changed the potency of amine-based diselenide.     

咪唑类氮氧自由基的合成及其DPPH清除能力的研究

目的:合成8种新型咪唑类氮氧自由基(4a~4h),并探讨其对1,1-二苯基-2-三硝基苯肼自由基(DPPH)的清除作用。方法:本文以2-硝基丙烷为原料,经烷基化、还原、缩合及氧化反应等步骤,合成8种新型咪唑类氮氧自由基(4a~4h)。将4a~4h分别与DPPH作用,使用紫外-可见分光光度法测定其中DPPH的浓度,考察4a~4h对DPPH自由基的清除作用,以四甲基哌啶氮氧自由基(Tempol)作为阳性对照。结果:合成中间体及终产物经~1H NMR、HRMS、EPR等光谱数据确证了结构。通过DPPH自由基清除实验,结果显示所合成的8种新型咪唑类氮氧自由基对DPPH均有清除作用。结论:合成了新型咪唑类氮氧自由基,并对其合成方法进行了重要改进。在对DPPH自由基清除能力方面,8种化合物在一定浓度范围(0.01μmol/mL-2.4μmol/mL)内,清除作用与浓度成依赖性增长关系。其中,4b与Tempol相当,4a优于阳性对照Tempol,具有进一步开发研究的潜在价值。     

Phytochemical Analysis and Free Radical Scavenging Activity of Medicinal Plants Gnidia glauca and Dioscorea bulbifera

Gnidia glauca and Dioscorea bulbifera are traditional medicinal plants that can be considered as sources of natural antioxidants. Herein we report the phytochemical analysis and free radical scavenging activity of their sequential extracts. Phenolic and flavonoid content were determined. Scavenging activity was checked against pulse radiolysis generated ABTS^•+ and OH radical, in addition to DPPH, superoxide and hydroxyl radicals by biochemical methods followed by principal component analysis. G. glauca leaf extracts were rich in phenolic and flavonoid content. Ethyl acetate extract of D. bulbifera bulbs and methanol extract of G. glauca stem exhibited excellent scavenging of pulse radiolysis generated ABTS^•+ radical with a second order rate constant of 2.33×10⁶ and 1.72×10⁶, respectively. Similarly, methanol extract of G. glauca flower and ethyl acetate extract of D. bulbifera bulb with second order rate constants of 4.48×10⁶ and 4.46×10⁶ were found to be potent scavengers of pulse radiolysis generated OH radical. G. glauca leaf and stem showed excellent reducing activity and free radical scavenging activity. HPTLC fingerprinting, carried out in mobile phase, chloroform: toluene: ethanol (4: 4: 1, v/v) showed presence of florescent compound at 366 nm as well as UV active compound at 254 nm. GC-TOF-MS analysis revealed the predominance of diphenyl sulfone as major compound in G. glauca. Significant levels of n-hexadecanoic acid and octadecanoic acid were also present. Diosgenin (C₂₇H₄₂O₃) and diosgenin (3á,25R) acetate were present as major phytoconstituents in the extracts of D. bulbifera. G. glauca and D. bulbifera contain significant amounts of phytochemicals with antioxidative properties that can be exploited as a potential source for herbal remedy for oxidative stress induced diseases. These results rationalize further investigation in the potential discovery of new natural bioactive principles from these two important medicinal plants.     

中药地榆提取物对自由基的清除作用

本文采用三种分光光度法,测定了中药地榆提取物不同极性溶剂萃取所得各部分对羟自由基和超氧阴离子自由基的清除作用,以BHT为参照.结果表明:中药地榆提取物各萃取部分除石油醚层外,其它各萃取部分对·OH自由基都有清除作用,且随着提取物浓度的增加,清除率逐渐增高;对O2-自由基没有明显的清除作用.其中乙酸乙酯萃取部分对·OH自由基的清除作用最强.     

黄鳝清除氧自由基作用的研究

采用化学发光法建立四个活性氧体外模型分析黄鳝粘液、血液、粗多糖清除氧自由基和抑制脂质过氧化作用。结果表明:黄鳝粘液、血液和粗多糖具有清除超氧阴离子自由基(O2·)、羟自由基(·OH)、过氧化氢(H2O2)和抑制脂质过氧化(LPO)作用。清除O2·的IC50分别为5.10±2.68μg/mL、3.62±1.56μg/mL、7.19±1.19μg/mL;清除·OH的IC50分别为5.86±1.54μg/mL、3.36±1.36μg/mL、7.93±0.50μg/mL;清除H2O2的IC50分别为6.91±1.29μg/mL、5.92±0.39μg/mL、8.21±0.61μg/mL;抑制LPO的IC50分别为8.11±0.83μg/mL、6.90±0.51μg/mL、7.62±1.01μg/mL。提示黄鳝血液清除氧自由基作用最明显,粘液次之,最弱为粗多糖。     

盐穗木金属硫蛋白HcMT的体外自由基清除活性及抗氧化能力*

目的: 原核表达盐穗木(Halostachys caspica C. A. Mey.)金属硫蛋白HcMT并探究其抗氧化活性。方法: 构建原核表达载体pET-32a-HcMT,转化至大肠杆菌Escherichia coli BL21,加入Zn²⁺胁迫培养(终浓度为200 μmol/L),分离纯化得到Zn-HcMT,测定Zn-HcMT自由基清除活性和总抗氧化能力,制备复合物Zn-HcMT/TiO₂并做FTIR表征。结果: 通过原核表达获得融合蛋白Zn-HcMT,对·OH、O₂·^-、DPPH自由基具有较强的清除活性,对·OH、O₂·^-的IC₅₀分别为0.386 mg/mL、0.038 mg/mL。融合蛋白浓度为0.01 mg/mL时,对DPPH清除率达(37.43 ± 0.006 8)%,浓度为0.3mg/mL时TEAC(trolox-equivalent antioxidant capacity)值为(1.023 ± 0.01)mmol/L,融合蛋白还原力A₇₀₀为0.142 ± 0.055,FTIR图谱同时表现了Zn-HcMT和TiO₂吸收特性。结论: Zn-HcMT具有良好的清除ROS活性及较强的抗氧化能力,在化妆品领域有潜在应用前景。     

Superoxide Scavenging Activity of Spin-Labeled Nitrosourea and Triazene Derivatives

Superoxide scavenging activities (SSA) of newly synthesized spin-labeled nitrosourea and triazene derivatives, and their precursor nitroxides were investigated by the ESR/spin-trapping method using the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and hypoxanthine/xanthine oxidase as the superoxide-generating system. The spin-labeled nitrosoureas, triazenes and their precursor nitroxides exhibited excellent SSA, whereas clinically used nitrosourea and triazene, which do not contain the nitroxide moiety, did not show any SSA. Furthermore, it was deduced that these nitroxides scavenge superoxide by redox cycling between nitroxide and corresponding hydroxylamine.