番木瓜的抗氧化作用研究

目的探讨番木瓜的抗氧化作用。方法红细胞溶血、肝匀浆MDA生成及羟自由基生成用比色法测定,超氧化物歧化酶活力用羟胺法测定。结果番木瓜提取液体外给药能明显抑制H₂O₂所致红细胞溶血,并抑制小鼠肝匀浆自发性或Fe²⁺-V itC诱发的脂质过氧化反应。对H₂O₂所产生的羟自由基亦有直接的清除作用,并可提高大鼠血浆超氧化物歧化酶活力。结论番木瓜具有抗氧化作用。     

过氧化氢诱导牛主动脉内皮细胞损伤和胞内Ca2+升高及钙拮抗剂的抑制作用

为探讨缺氧/缺血过程中自由基损伤与钙超载的关系,观察了过氧化氢(H₂O₂)诱导培养牛主动脉内皮细胞(BAEC)的损伤和胞内游离钙([Ca²⁺]i)的变化。结果表明,H₂O₂可剂量、时间依赖地诱导BAEC活性下降(MTT值下降),脂质过氧化产物丙二醛(MDA)生成显著增加,同时伴有[Ca²⁺]i迅速显著升高。钙拮抗剂硝苯地平可剂量依赖地抑制H₂O₂引起的[Ca²⁺]i升高;同时能显著升高BAEC的MTT值,降低MDA生成,有效对抗H₂O₂诱导的BAEC损伤。提示,H₂O₂诱导内皮损伤可能与升高[Ca²⁺]i有关,Ca²⁺超载可能是活性氧致损伤的途径之一。钙拮抗剂对活性氧损伤具有一定保护作用。     

水溶性金属卟啉的合成、表征及其清除有毒活性氧的研究

目的合成并结构表征了4种水溶性金属卟啉配合物［5，10，15，20-四［4-(4′-吡啶-1)丁氧基苯基］金属卟啉溴化盐［锌卟啉(I)、铜卟啉(II)、锰卟啉(III)和钴卟啉(IV)］，作为抗活性氧(O^-₂，H₂O₂，HO·)模拟酶。方法 核黄素-蛋氨酸光照测其清除O^-₂作用，H₂O₂氧化Vit C法测其催化H₂O₂的分解，Fenton-苯甲酸钠荧光法测其对HO·清除作用，小鼠肝匀浆法测其抗脂质过氧化作用。结果1.0×10^-5~1.0×10^-6 mol·L^-1均具有良好的清除O^-₂作用；1.5×10^-6~1.0×10^-6 mol·L^-1均具有分解H₂O₂作用；2.0×10^-8~1.0×10^-8 mol·L^-1均具有清除HO·的功能；1.0×10^-7 mol·L^-1均可使脂质过氧化产物明显减少。结论合成4种水溶性金属卟啉配合物可作为抗多种活性氧(O^-₂，H₂O₂，HO·)模拟酶。     

异亚丙基莽草酸对H2O2损伤血管内皮细胞的保护作用

目的研究异亚丙基莽草酸(ISA)对血管内皮细胞损伤的保护作用。方法倒置显微镜下观察细胞形态学改变,MTT比色法检测细胞活性,用硝酸还原酶法测定细胞培养液中NO的含量。放射免疫法测定细胞培养液中前列环素代谢物6-酮-前列腺素F_1α(6-keto-PGF_1α)含量,比色法测定培养液及细胞裂解液的乳酸脱氢酶(LDH)活性并计算LDH的释放率。结果ISA可明显改善H₂O₂所致的内皮细胞变形、皱缩等损伤表现。1～100 μmol·L^-1 ISA可浓度依赖性的减轻H₂O₂引起的细胞活性降低和LDH释放,并促进H₂O₂诱导的血管内皮细胞释放NO和前列环素。结论异亚丙基莽草酸对H₂O₂损伤血管内皮细胞具有保护作用。     

人参皂苷Rg1对H2O2诱导的HaCaT细胞氧化损伤保护作用研究

目的 观察人参皂苷Rg₁对H₂O₂诱导的HaCaT细胞氧化损伤保护作用,并探讨其机制。方法 体外培养HaCaT细胞, H₂O₂诱导细胞建立氧化应激损伤模型,分为空白组、H₂O₂损伤组、人参皂苷Rg₁保护组。细胞增殖与毒性检测试剂盒(CCK-8)检测细胞存活率,Hochest染色法检测细胞凋亡情况,活性氧检测试剂盒测定细胞活性氧(ROS)水平,Western blot检测细胞中caspase-3、caspase-6、caspase-8、GAPDH蛋白表达。结果 H₂O₂诱导HaCaT细胞半数抑制浓度为100 μg?mL^-1;与H₂O₂损伤组比较,5、10和15mg?L^-1人参皂苷Rg₁预处理后,HaCaT细胞存活率明显升高(P<0.05),细胞核皱缩损伤状态明显改善,细胞凋亡数量显著减少。同时,人参皂苷Rg₁预处理可显著降低HaCaT细胞ROS水平,下调凋亡相关标志蛋白-活化型caspase-3、caspase-6、caspase-8蛋白表达水平。结论 人参皂苷Rg₁对H₂O₂诱导的HaCaT细胞氧化应激损伤具有一定的保护作用,其机制可能与增强细胞清除自由基能力及抑制凋亡相关。     

DJ-1保护多巴胺能神经元抵抗过氧化氢氧化应激损伤的研究

目的 探讨DJ-1保护多巴胺能神经元免受过氧化氢(H₂O₂)损伤的机制。 方法 使用神经生长因子(NGF)将大鼠嗜铬细胞瘤细胞(PC12细胞)诱导为多巴胺能神经元模型。H₂O₂处理引起细胞氧化应激损伤模型,CCK-8试剂盒检测细胞活性,DHE染色检测细胞内ROS水平。PI / Hoechst染色检测细胞凋亡,蛋白质免疫印迹法(Western blot)检测DJ-1和TH蛋白的表达。构建DJ-1过表达载体,检测DJ-1对H₂O₂中PC12细胞的保护作用及对细胞内活性氧(ROS)的影响。RT-qPCR检测α-synuclein,p53,Bax,Bcl-2的表达变化。 结果 H₂O₂处理可显着降低PC12细胞的活性,H₂O₂处理24 h以上可引起细胞凋亡。H₂O₂处理下调DJ-1蛋白和TH蛋白的表达,并且在RNA水平上α-突触核蛋白的表达增加。另外 p53, Bax和 caspase-3表达增加, Bcl-2表达减少。DJ-1的过表达可以抑制H₂O₂引起的ROS增加,DJ-1可以维持细胞活性,减少H₂O₂的凋亡。在RNA水平抑制α-突触核蛋白,p53,bax,bcl-2的凋亡和抗凋亡基因表达变化。 结论 DJ-1能够抑制H₂O₂引起的 ROS水平升高,减少α-synuclein积累,抑制 p53,凋亡基因如 bax的表达减弱了多巴胺能神经元中H₂O₂诱导的氧化应激损伤。     

基于能量代谢分析白藜芦醇对H2O2诱导SH-SY5Y细胞保护作用

目的 基于能量代谢探究白藜芦醇对H2O2诱导的人神经母细胞瘤SH-SY5Y细胞氧化损伤的保护作用。方法 选取20、10、5、1 μmol•L^-1的白藜芦醇（Res）处理SH-SY5Y细胞24 h后,加入1.2 mmol•L^-1的H₂O₂,继续培养24 h,采用MTT法测定细胞活力,流式细胞术检测细胞凋亡率,试剂盒检测糖代谢相关酶己糖激酶（HK）、磷酸果糖激酶（PFK）、丙酮酸激酶（PK）、琥珀酸脱氢酶（SDH）、乳酸脱氢酶（LDH）活力以及葡萄糖消耗量、ATP含量,Western blot法检测低氧诱导因子1α（HIF-1α）和葡萄糖转运体1（GLUT-1）表达。结果 1.2 mmol•L^-1的H₂O₂造成SH-SY5Y细胞氧化损伤,细胞活力降低,细胞凋亡率升高（P<0.01）;与H₂O₂氧化损伤组相比,20、10、5 μmol•L^-1白藜芦醇组细胞活力升高,细胞凋亡率显著降低（P<0.01）;PFK、PK、SDH活力及ATP含量、葡萄糖消耗量显著升高,HK活力和细胞外LDH活力明显降低（P<0.01）;GLUT-1表达量显著升高,HIF-1α表达量显著降低（P<0.01）。结论 20、10、5 μmol•L^-1的白藜芦醇调控GLUT-1和HIF-1α蛋白表达,提高细胞糖代谢酶活力,增加产能,对H₂O₂诱导的SH-SY5Y细胞氧化损伤发挥保护作用。     

黄精多糖调控SIRT1/AMPK/PGC-1α信号通路改善H2O2诱导的HT22细胞氧化损伤

目的 研究黄精多糖对H₂O₂诱导的HT22细胞氧化应激损伤及其对SIRT1/AMPK/PGC-1α信号通路关键信号分子的影响。方法 建立H₂O₂诱导HT22细胞氧化损伤模型，黄精多糖干预后，观察黄精多糖对HT22细胞活性乳酸脱氢酶（lactate dehydrogenase，LDH）释放的影响，检测超氧化物歧化酶（superoxide dismutase，SOD）活性、丙二醛（malondialdehyde，MDA）含量、还原型谷胱甘肽（glutathione，GSH）含量、线粒体呼吸链酶复合体Ⅰ活性、腺嘌呤核苷三磷酸（adenosine triphosphate，ATP）含量，Western blotting检测细胞中SIRT1、AMPK、p-AMPK及PGC-1α蛋白的表达。结果 与模型组相比，黄精多糖（100，200，400 μmicro；g·mL^-1）明显提高细胞活性（P<0.05或P<0.01），降低LDH释放（P<0.05或P<0.01），减少MDA的产生（P<0.05或P<0.01），增加SOD活力和GSH含量（P<0.05或P<0.01），可提高ATP含量及线粒体呼吸链酶复合体Ⅰ活性。此外，黄精多糖还能够上调细胞中SIRT1、p-AMPK及PGC-1α蛋白的表达。结论 黄精多糖能通过增强细胞内抗氧化活性，提高HT22细胞的存活率，改善线粒体功能，从而保护细胞抗氧化损伤，其作用机制与激活SIRT1/AMPK/PGC-1α信号通路有关。     

羟乙基葛根素对过氧化氢致牛脑微血管内皮细胞损伤的保护作用

目的研究牛脑微血管内皮细胞(BCMEC)过氧化损伤机制并探讨羟乙基葛根素对牛脑微血管内皮细胞损伤的保护作用。方法用MTT法和LDH活性检测测定BCMEC的损伤；倒置相差显微镜下一般形态学观察、透射电子显微镜超微结构观察及流式细胞术测定BCMEC凋亡变化。结果H₂O₂ (200 μmol·L^-1)损伤BCMEC后，细胞存活率下降，LDH释放增加，羟乙基葛根素和edaravone可减轻此损伤。H₂O₂ (100 μmol·L^-1)可诱导BCMEC凋亡，羟乙基葛根素 和edaravone对此有保护作用。结论羟乙基葛根素和edaravone对H₂O₂导致的BCMEC坏死和凋亡有保护作用，该作用与其抗氧化作用有关。     

芦荟中芦荟苷清除超氧阴离子自由基的ESR研究

目的　从分子水平探讨芦荟保健美容的作用机制。方法　利用电子自旋共振(ESR)法,以二甲基亚砜在碱性条件下产生超氧阴离子自由基(O₂^-·)体系,检测芦荟中主要有效成分芦荟苷清除O₂^-·的能力。结果　芦荟苷具有良好的清除超氧阴离子自由基(O₂^-·)的作用,芦荟苷浓度为0. 26mg/mL时,对O₂^-·的清除率达100%。结论　芦荟的保健美容作用可能与其主要有效成分芦荟苷具有清除超氧阴离子自由基的能力有关。     

山药多糖RDPS-I的结构分析及抗肿瘤活性

目的研究山药多糖的化学结构和抗肿瘤活性。方法用水提取山药块茎粗多糖,经Sevag反复脱蛋白8次,透析后经DEAE-cellulose及Sephadex G-100柱色谱纯化得山药多糖RDPS-I。经完全酸水解、部分酸水解,用PC,GC,IR,高碘酸氧化,Smith降解,甲基化分析,¹HNMR及¹³CNMR等研究山药多糖的化学结构。并用小鼠移植性实体瘤研究了RDPS-I的体内抗肿瘤作用。结果RDPS-I的分子量为41 000,比旋光度为［α］²⁰_D=+188.4°(c 0.80,H₂O),特性粘度为［η］=16.48×10^-3(g·mL^-1)。RDPS-I是由葡萄糖、甘露糖和半乳糖以1∶0.4∶0.1的摩尔比组成,以α-D-(1→3)-Glcp为主链,在6-O位有α-D-(1→2)-Manp-β-D-1)-Galp支链的杂多糖。RDPS-I对移植性黑色素B16和Lewis肺癌有很强的抑制作用。结论RDPS-I是由葡萄糖、甘露糖和半乳糖构成的杂多糖,有很强的体内抗肿瘤活性。     

黄芪多糖的研究

从中药黄芪Aslragalus mongholicus Bunge.的水提液中分离得到两种葡聚糖AG-1、AG-2和两种杂多糖AH-1、AH-2。该四种多糖经电泳、凝胶柱层析等证实均为单一组分。AG-1为水溶性,经水解、过碘酸氧化、甲酸生成、Smith降解、乙酰解、红外、C-13核磁共振等确定为α(1→4)(1→6)葡聚糖、α(1→4)与口(1→6)甙键糖基的组成比例约为5:2。AG-2不溶于水,为α(1→4)葡聚糖。AH-1为水溶性酸性多糖,水解后纸层析检出含己糖醛酸(半乳糖醛酸和葡萄糖醛酸)、葡萄糖、鼠李糖、阿拉伯糖,其分子比值为1:0.04:0.02:0.01。AH-2为水溶性、水解后用纸层析和气相层析检出葡萄糖和阿拉伯糖,其分子比值为1:0.15。AG-1、AH-1具有某些免疫促进作用。     

Furostanol oligoglycosides from Asparagus cochinchinensis

Three new furostanol oligoglycosides, named aspacochioside A (1), B (2) and C (3), together with the known compound 3-O-[{α-l-rhamnopyranosyl-(1→4)}{β-d-glucopyranosyl}]-26-O-[β-d-glucopyranosyl]-(25S)-5β-spirostane-3β-ol were isolated from the roots of Asparagus cochinchinensis. Their structures were elucidated by spectroscopic techniques (IR, HR-ESIMS, ESIMS/MS, 1D and 2D NMR) and chemical methods as 3-O-[{α-l-rhamnopyranosyl-(1→4)}{β-d-glucopyranosyl}]-26-O-[β-d-glucopyranosyl]-(25S)-5β-furostane-3β,22α,26-triol (1), 3-O-[{α-l-rhamnopyranosyl-(1→4)}{β-d-glucopyranosyl}]-26-O-[β-d-glucopyranosyl]-22α-methoxy-(25S)-5β-furostane-3β,26-diol (2), and 3-O-[{α-l-rhamnopyranosyl-(1→4)}{β-d-glucopyranosyl}]-26-O-[β-d-glucopyranosyl]-(25S)-5β-furost-20(22)-en-3β,26-diol (3).     

Pregnane glycosides from Dracaena cochinchinensis

Two new pregnane glycosides, named dracaenoside C and D, were isolated from the fresh stems of Dracaena cochinchinensis. Their structures were established as 3β,14α-dihydroxypregna-5,16(17)-diene-20-one?3-O-α-L-rhamnopyranosyl(1→2)[α-L-rhamnopyranosyl(1→4)]-β-D-glucopyranoside (1) and 3β,14α-dihydroxypregna-5,16(17)-diene-20-one?3-O-α-L-rhamnopyranosyl(1→2)[β-D-glucopyranosyl(1→3)]-β-D-glucopyranoside (2) by means of 2D NMR spectral and chemical methods.     

A polysaccharide from the stems of Rubus amabilis Focke and its immunological enhancement activity

A water-soluble polysaccharide (named RAP) was newly isolated from the stems of Rubus amabilis. Structural confirmation of the polysaccharide was provided by hydrolysis, periodate oxidation, Smith degradation, and methylation analysis, combined with nuclear magnetic resonance (NMR), capillary electrophoresis (CE), infrared spectroscopy (IR), and gas chromatography-mass spectra (GC-MS). In vitro immunological enhancement activity was characterized using the proliferative activity of spleen lymphocytes and phagocytic activity of peritoneal macrophages in mice. The polysaccharide was mainly composed of xylose, arabinose, glucose, rhamnose, galactose, mannose, glucuronic acid, and galactocuronic acid in the molar ratio of 1.0:6.9:0.8:1.1:6.9:0.3:0.5:3.3, with the average molecular weight of 26.2 kDa. The linkage types of netural monosaccharides were as follows: the arabinose was →2) Ara (1→ and galactose were Gal (1→, →3) Gal (1→, →3,6) Gal (1→, →2,3,6) Gal (1→ and →2,3,6) Gal_f (1→. Xyl (1→, →6) Glc (1→, →2) Glc (1→, →3) Rha (1→, Rha (1→ and Man (1→ were also found in the structure. RAP-B-2 could improve the proliferative activity of spleen T cells and B cells and boost phagocytic activity of peritoneal macrophages at the concentration of 50 μg/ml (p < 0.05, p < 0.01).     

Isolation,purification, and structural elucidation of polysaccharides from Alhagi-honey

The polysaccharide extract (PE) of Uyghur medicinal preparation Alhagi-honey was prepared by water extraction and alcohol precipitation method. The purified polysaccharide AP1-1 was obtained from PE by macroporous adsorption resin chromatography, DEAE cellulose chromatography, and Sephadex gel chromatography; the homogeneity and the molecular weight of AP1-1 were determined by gel filtration; and the acid hydrolysis, periodate oxidation, Smith degradation, and NMR analysis were used to analyze the chemical structure of AP1-1. The result showed that AP1-1 was a homogeneous polysaccharide, whose relative molecular weight was 9.97 × 10⁴. Through high-performance capillary electrophoresis analysis, we found that its molecular structure was composed of mannose, glucose, galactose, and galacturonic acid with a molar ratio of about 1.1:1.9:3.9:2.1. The main chain of AP1-1 was mainly made up of → 4)β-d-GalpA-(1 → 4)β-d-GalpA-(1 → 4)-β-d-Galp-(1 → 4)-β-d-Galp-(1 → 6)α-d-Glcp-(1 → 4)α-d-Glcp(1 → , while the side chain is composed of → 6)-α-d-Glcp and 2-CH₃-α-d-Man.     

Note: A new biologically active flavonol glycoside from Psoralea corylifolia (Linn.)

A new biologically active flavonol glycoside (1) mp 264–265°C, C₃₂H₃₈O₂₀, [M]⁺ 742 (EIMS) has been isolated from the methanol-soluble fraction of the defatted seeds of Psoralea corylifolia (Linn.). It was characterised as the new flavonol glycoside 3,5,3′,4′-tetrahydroxy-7-methoxyflavone-3′-O-α-l-xylopyranosyl(1→3)-O-α-l-arabinopyranosyl(1→4)-O-β-d-galactopyranoside by several colour reactions, spectral analysis and chemical degradations. Compound 1 showed anti-microbial activity against various bacteria and fungi.     

Chemical synthesis and receptor binding of catfish somatostatin: a disulfide‐bridged β‐d‐Galp‐(1→3)‐α‐d‐GalpNAc O‐glycopeptide*

Abstract: The glycopeptide hormone catfish somatostatin (somatostatin‐22) has the amino acid sequence H‐Asp‐Asn‐Thr‐Val‐Thr‐Ser‐Lys‐Pro‐Leu‐Asn‐Cys‐Met‐Asn‐Tyr‐Phe‐Trp‐Lys‐Ser‐Arg‐Thr‐Ala‐Cys‐OH; it includes a cyclic disulfide connecting the two Cys residues, and the major naturally occurring glycoform contains d ‐GalNAc and d ‐Gal O‐glycosidically linked to Thr⁵. The linear sequence was assembled smoothly starting with an Fmoc‐Cys(Trt)‐PAC‐PEG‐PS support, using stepwise Fmoc solid‐phase chemistry. In addition to the nonglycosylated peptide, two glycosylated forms of somatostatin‐22 were accessed by incorporating as building blocks, respectively, N^α‐Fmoc‐Thr(Ac₃‐α‐D‐GalNAc)‐OH and N^α‐Fmoc‐Thr(Ac₄‐β‐D‐Gal‐(1→3)‐Ac₂‐α‐D‐GalNAc)‐OH. Acidolytic deprotection/cleavage of these peptidyl‐resins with trifluoroacetic acid/scavenger cocktails gave the corresponding acetyl‐protected glycopeptides with free sulfhydryl functions. Deacetylation, by methanolysis in the presence of catalytic sodium methoxide, was followed by mild oxidation at pH 7, mediated by N^α‐dithiasuccinoyl (Dts)‐glycine, to provide the desired monomeric cyclic disulfides. The purified peptides were tested for binding affinities to a panel of cloned human somatostatin receptor subtypes; in several cases, presence of the disaccharide moiety resulted in 2‐fold tighter binding.     

天门冬化学成分的分离与鉴定

目的对中药天门冬(Asparagus cochinchinensis(Lour.)Merr.)的化学成分进行研究。方法采用硅胶柱色谱、制备薄层色谱、重结晶等方法进行分离纯化,通过理化性质和核磁共振波谱数据鉴定化合物结构。结果分离得到8个化合物,分别鉴定为(+)-4′-O-methyl-nyasol(1)、(+)-nyasol(2)、5,7-二羟基-6,8,4′-三甲氧基黄酮(5,7-dihydroxyl-6,8,4′-trimethoxylflavone,3)、菝葜皂苷元(sarsasapogenin,4)、5-羟甲基糠醛(5-hydroxymethylfuraldehyde,5)、β-谷甾醇(β-sitosterol,6)、胡萝卜苷(daucosterol,7)和豆甾醇(stigmasterol,8)。结论化合物3为首次从天门冬属中分离得到,化合物1、8为首次从该植物中分离得到。     

用核磁共振新技术测定日本续断皂甙E1的结构

从日本续断Dipsocus japunicus Miq.根的乙醇提到物中得到一个新三萜皂甙(5糖甙)，命名为日本续断皂甙E₁(japondipsaponin E₁)。用化学方法及¹HNMR,¹³CNMR,¹H-¹H COSY，一维多重接力COSY，选择性远程DEPT和三重共振NOE差谱等方法，鉴定其结构为3-O-α-L-吡喃鼠李糖(1-3)-β-D-吡喃葡萄糖（1→3）-α-L-吡喃鼠李糖（1→2）-α-L-吡喃阿拉伯糖常春藤皂甙元28-O-β-D-吡喃葡萄糖甙。