黄酮醇-3-O-D-木糖(1→2)-L-鼠李糖甙类化合物的NMR谱研究

用2D NMR技术研究了从朝鲜淫羊藿中分离的一个黄酮醇-3-O-D-木糖-鼠李糖甙的结构,确定其双糖为1→2连接,并明确了判断同类黄酮醇-3-O-木糖基(1→2)-鼠李糖甙的简易标准.     

用2D NMR确定黄酮醇-3-O-L-吡喃鼠李糖(1→2)-L-呋喃阿拉伯糖甙的双糖结构

用2D NMR (¹H-¹H COSY和¹H-¹³C COSY)技术研究了从鹰瓜花中分离到的黄酮醇-3-O-吡喃鼠李糖基呋喃阿拉伯糖甙的双糖结构,明确其双糖为1→2连接.     

黄酮甙类化合物中的酰基取代及其取代位置的确定

研究了黄酮甙类化合物的酰基取代现象，借助２ Ｄ ＮＭＲ技术，举例研究了一黄酮醇三乙酰基三糖甙的结构，着重研究糖上酰基的取代位置，并归纳总结了黄酮甙类化合物中各种常见的酰基的＾１３ ＣＮＭＲ谱及其取代所产生的位移现象。     

黄酮类化合物中苯环13C NMR化学位移计算

介绍了黄酮类化合物中苯环¹³C NMR化学位移计算方法.这些化合物包括黄酮、黄烷酮、黄酮醇、黄烷酮醇、黄酮甙、黄烷、异黄酮和异黄烷酮等.     

川续断中新七糖三萜皂苷的核磁共振研究

从中药川续断根部的乙醇提取物中分得一个新的三萜皂甙.经过测定,它为:3-O[α-L-吡喃鼠李糖(1→3)][-β-D吡喃葡萄糖(1→4)]-β-D吡喃葡萄糖(1→3)-α-L-吡喃鼠李糖(1→2)-β-L-吡喃阿拉伯糖-常春藤甙元-28-O-β-D-吡喃葡萄糖(1→6)-β-D-吡喃葡萄糖酯甙.本文采用一维SEMDY,旋转坐标NOE差谱和选择性远程DEPT新技术相结合测定该化合物的糖链结构.     

槲皮素-3-鼠李糖-(6-对羟基反式桂皮酰)葡萄糖甙1-2连接的NMR谱证据

用2D NMR技术研究了从银杏叶提取物中分离的一个黄酮双糖甙[槲皮素-3-鼠李糖-(6-对羟基反式桂皮酰)葡萄糖甙]的结构,对鼠李糖部分的¹H NMR,¹³C NMR化学位移进行了归属.¹³C化学位移和¹H NOE相关性都证明鼠李糖为1″-2″连接.     

一系列薯蓣皂甙元-β-D葡萄糖基-(1→2)和(1→3)-β-D葡萄糖甙的1H和13C NMR归属

用同核和异核二维核磁共振方法全归属了一系列合成的薯蓣皂甙元-β-D葡萄糖甙的¹H和¹³C核磁共振谱线.这些薯蓣葡萄糖甙是薯蓣皂甙元-β-D葡萄糖甙(1),薯蓣皂甙元-β-D葡萄糖基-(1→2)-β-D葡萄糖甙(2),薯蓣皂甙元,-β-D葡萄糖基-(1→3)-β-D葡萄糖甙(3),薯蓣皂甙元[-β-D葡萄糖基-(1→2)-β-D葡萄糖基(1→3)-β-D葡萄糖甙(4)以及薯蓣皂甙无[-α-L鼠李糖基-(1→2)]-β-D葡萄糖基-(1→3)-β-D葡萄糖甙(5).     

一系列薯蓣皂甙元-α-L鼠李糖基-(1→2)和(1→4)-β-D葡萄糖甙的1H和13C NMR归属

用同核和异核二维核磁共振方法全归属了一系列合成的薯蓣皂甙元-α-鼠李糖基-β-D葡萄糖甙的¹H和¹³C核磁共振谱线.这些薯蓣葡萄糖甙是薯蓣皂甙元-β-D葡萄糖甙(1),薯蓣皂甙元-α-L鼠李糖基(1→2)-β-D葡萄糖甙(2),薯蓣皂甙元-α-L鼠李糖基(1→4)-β-D葡萄糖甙(3),薯蓣皂甙元[-α-鼠李糖基-(→2)]-α-L鼠李糖基→-(1→4)-β-D葡萄糖甙(4)以及薯蓣皂甙元[-α-L鼠李糖基-(1→2)]-β-D阿拉伯糖基-(1→4)-β-D葡萄糖甙(5).     

三萜大叶冬青甙I和苦丁冬青甙K的NMR研究

大叶冬青甙I和苦丁冬青甙 K系分别从Ilex latifolia Thunb.和Ilex kudincha C. J. Tseng的叶子中分离得到的三萜皂甙.用化学和波谱方法,特别是2D NMR波谱技术,推定它们的结构分别为3-O-β-D-吡喃葡萄糖-(1→3)-α-L-吡喃阿拉伯糖-30(S)-3β,19α,23-trihydroxy-urs-12-en 28-oic acid 28-O-β-D-吡喃葡萄糖甙和3-O-［α-L-吡喃鼠李糖-(1→2)］-［β-D-吡喃葡萄糖-(1→2)-β-D-吡喃葡萄糖-(1→3)］-α-L-吡喃阿拉伯糖-3β,19α,20β-trihydroxyurs-12-en-28-oic acid 28-O-［α-L-吡喃鼠李糖-(1→2)］-β-D-吡喃葡萄糖甙,并对其NMR信号进行了全归属.     

长枝沙菜Hypnea Charoides次级代谢物的分离与结构鉴定

对采自中国南海的红藻长枝沙菜 Hypnea Charoides的次级代谢物进行研究 ,从中分离得到 4个化合物 ,通过核磁共振、质谱等现代波谱分析技术确定其结构为 :豆甾 - 5 ,2 2 -二烯 - 3β-醇 - 3- o- β- D-吡喃葡萄糖甙 ( Ⅰ)、1 - o-十六碳酰基 -甘油酯 ( Ⅱ )、棕榈酸 ( Ⅲ )、正二十四烷 ( Ⅳ ) ,这些化学成分均首次从长枝沙菜中分离得到。     

镜泊湖水体水溶性有机物荧光特性研究

通过黑龙江省区域镜泊湖水体6个点位样品采集(样品号J1-J6),利用荧光检测技术,结合三维荧光光谱区域积分(FIR),研究了水溶性有机物(DOM)的荧光特性。传统荧光光谱显示J4和J5 DOM分子缩合度较高;三维荧光光谱显示J6点位DOM中类蛋白特征峰最为显著;对所有点位DOM的三维荧光光谱5个区域积分(A_Ⅰ,A_Ⅱ,A_Ⅳ：类蛋白区域;A_Ⅲ：类富里酸区域：A_Ⅴ：类胡敏酸区域)显示：所有点位DOM区域积分中A_Ⅴ区域占有比例最大,并且以J4和J5点位最高,J6点位最低。通过对腐殖酸区域(A_Ⅲ和A_Ⅴ积分比例之和)与类蛋白区域(A_Ⅰ,A_Ⅱ,A_Ⅳ积分比例之和)积分比值表明,J4(4.94)和J5(5.18)点位比值相近;J1(3.52)和J2(3.66)点位比值接近;最小值为J6点位(2.11)。综合以上分析证实,镜泊湖水体各点位DOM腐殖化程度为：J4,J5>J1,J2>J3>J6点位。     

Biodegradable cystamine spacer facilitates the clearance of Gd(III) chelates in poly(glutamic acid) Gd-DO3A conjugates for contrast-enhanced MR imaging

Poly(L-glutamic acid) (PGA)-cystamine-[gadolinium (Gd)-DO3A] was prepared in high yield with a high Gd-DO3A conjugation efficiency. Approximately 55% of the carboxylic groups in PGA were loaded with Gd-DO3A via cystamine as the spacer. Cystamine can be readily cleaved by endogenous thiols to release the Gd(III) chelates from the conjugate facilitating Gd(III) excretion after the magnetic resonance imaging (MRI). The contrast-enhanced MRI with PGA-cystamine-(Gd-DO3A) was investigated in mice bearing MDA-MB-231 breast carcinoma xenografts. PGA-1,6-hexanediamine-(Gd-DO3A), a paramagnetic polymer conjugate of a nondegradable spacer, was used as a control. Both conjugates resulted in similar contrast enhancement in the heart, vasculature, liver and kidneys in the first hour post injection. More substantial signal intensity reduction was observed for PGA-cystamine-(Gd-DO3A) in these organs than PGA-1,6-hexanediamine-(Gd-DO3A) due to release of the Gd chelates from PGA-cystamine-(Gd-DO3A) after the cleavage of the disulfide spacer by the endogenous thiols. Both conjugates resulted in similar tumor enhancement with approximately 70% increased signal intensity in the tumor periphery and 10-40% increased signal intensity in tumor interstitium. No cross-reaction was observed between PGA-cystamine-(Gd-DO3A) and human serum albumin, a plasma protein containing a cysteine residue. PGA-cystamine-(Gd-DO3A) resulted in significantly lower Gd(III) tissue retention than PGA-1,6-hexanediamine-(Gd-DO3A) 10 days after the injection in the mice (P<.05). The conjugation of Gd(III) chelates to biomedical copolymers via the degradable disulfide spacer resulted in significant contrast enhancement in the blood pool and tumor tissue but minimal long-term Gd(III) tissue retention.     

基于p53DNA的泽泻醇抗肿瘤分子机制研究

研究泽泻醇类化合物23-乙酰泽泻醇B(alisol B 23-acetate, 23B)、24-乙酰泽泻醇A(alisol A 24-acetate, 24A)混合物(24A∶23B含量比=1∶1)与抑癌基因p53DNA的作用机理,探讨泽泻醇类化合物抗肿瘤作用的分子机制。紫外-可见吸收光谱法、荧光光谱法与分子模拟联用探讨23B,24A及24A-23B混合物与p53DNA的作用方式。紫外光谱显示泽泻醇单体与其混合物部分嵌插入p53DNA,他们使p53DNA紫外吸收降低的程度为：24A∶23B(1∶1)>23B>24A。荧光光谱显示泽泻醇单体及其混合物与p53DNA的相互作用模式均为嵌插结合,结合强度为：24A∶23B(1∶1)>23B>24A。分子模拟显示,泽泻醇单体及其混合物与p53DNA结合能的大小顺序为：24A∶23B (1∶1)>23B>24A,23B与p53DNA f 链的腺嘌呤脱氧核苷酸(DA4)形成1个氢键,24A-23B复合物与p53DNA的DA4、胸腺嘧啶脱氧核苷酸(DT19)形成4个氢键。24A,23B及其混合物与p53DNA结合的强度顺序：24A∶23B (1∶1)>23B>24A,表明24A和23B对抗癌靶点p53DNA具有协同作用,三者与p53DNA的作用方式均为部分嵌插结合。同时,泽泻醇化合物母环C14-和结构中的空间位阻,p53DNA f 链的DA4中磷酸上的氧原子为泽泻醇类化合物与p53DNA相互作用的关键结合位点,是该类泽泻醇发挥抗肿瘤作用的活性中心。24A侧链C19-上的羟基,p53DNA f 链的DA4中腺嘌呤上的氮原子和氧原子,e链的DT19中胸腺嘧啶上的氧原子为泽泻醇类化合物协同增效作用的关键。     

Agglomeration,sedimentation, and cellular toxicity of alumina nanoparticles in cell culture medium

The cytotoxicity of alumina nanoparticles (NPs) was investigated for a wide range of concentration (25–200 μg/mL) and incubation time (0–72 h) using floating cells (THP-1) and adherent cells (J774A.1, A549, and 293). Alumina NPs were gradually agglomerated over time although a significant portion of sedimentation occurred at the early stage within 6 h. A decrease of the viability was found in floating (THP-1) and adherent (J774A.1 and A549) cells in a dose-dependent manner. However, the time-dependent decrease in cell viability was observed only in adherent cells (J774A.1 and A549), which is predominantly related with the sedimentation of alumina NPs in cell culture medium. The uptake of alumina NPs in macrophages and an increased cell-to-cell adhesion in adherent cells were observed. There was no significant change in the viability of 293 cells. This in vitro test suggests that the agglomeration and sedimentation of alumina NPs affected cellular viability depending on cell types such as monocytes (THP-1), macrophages (J774A.1), lung carcinoma cells (A549), and embryonic kidney cells (293).     

The effect of task block arrangement on the detectability of activation in fMRI

The effect of task block arrangements on the detection of brain activation was investigated. Sessions of functional magnetic resonance imaging (fMRI) including the same number of two different task conditions but with different arrangements were compared. The two task conditions were, A) Ellipse-shaped black and white checkerboard flicker stimulation at 4.2 Hz covering the bilateral visual field, and B) the same flicker stimuli covering only the left visual field. In the rest blocks (0), the subjects looked at a fixation point. Four different task block arrangements were compared, 1) A0 (0A0A0A0) and B0 (0B0B0B0), 2) A0B0 (0A0B0A0B0A0B0), 3) AB0 (0AB0AB0AB0) and 4) AB (0ABABAB). Bilateral V1, V2, V3 and the left V5 were activated by condition A, and the right V1 and V2 by B. The activation in the left visual field by A0 was larger than in the other three conditions. In a differential analysis between conditions A and B, activation in the left V3 and V5 was declined by AB0 or AB. When rest blocks were located in the post-stimulus undershoot phase, the % signal change of the BOLD signal was emphasized, which caused augmented significance in the detection of the activity. It was indicated that the outcome of the activation map was influenced by the arrangement of task blocks, even though the same number of task blocks were repeated within the sessions. In fMRI studies, task conditions should be carefully compared within or across sessions considering the characteristics of hemodynamic response functions.     

Structure and photoluminescence study of type-II GaAs quantum wires and dots grown on nano-faceted (3 1 1)A surface

(3 1 1)A GaAs/AlAs corrugated superlattices (CSLs) and satellite (3 1 1)B and (1 0 0) SLs were studied using Raman spectroscopy, high-resolution transmittance electron microscopy (HRTEM) and photoluminescence (PL). The thickness of GaAs layers was varied from 1 monolayer (ML) to 10 ML, the thickness of AlAs barriers was 10 ML in (3 1 1) direction. The strongest modification of the Raman spectra is found for the case of partial (<1 nm) GaAs filling of the AlAs surface. The calculated and experimental Raman spectra demonstrated a good agreement for both complete (1 nm) and partial (<1 nm) GaAs filling of the AlAs surface. According to Raman and HRTEM data, in the case of partial filling of (3 1 1)A AlAs surface, GaAs forms quantum well wires of finite length (quantum dots). A drastic difference of PL from grown side-by-side (3 1 1)A and (3 1 1)B SLs was observed. A strong room temperature PL in the green–yellow spectral region was observed in GaAs/AlAs (3 1 1)A CSLs containing GaAs type-II quantum dots.     

镧系络合物的双向螯合剂--BCPDA的性质研究

对镧系络合物的双向螯合剂——4,7-二氯磺酰基苯基-1,10-菲咯啉-2,9-二羧酸(BCPDA)合成、表征和性质研究表明:1.通过IR光谱、1H NMR、熔点、元素分析证明其结构正确。2.BCPDA可溶于几种不同溶剂。3.几种体系的BCPDA溶液所得到的吸收光谱基本相同,且BCPDA的浓度与吸光度在1.00-1.20×10~2μmol·L-1范围内呈正比。4.BCPDA标记蛋白质和铕离子与BCPDA螯合连接实验证实了BCPDA的双向功能。     

高斯多峰拟合用于烷基葡萄糖苷临界胶束浓度测量

报道了可见吸收光谱线型的高斯多峰拟合用于新型非离子表面活性剂烷基葡萄糖苷(APG),如辛基-β-D-葡萄糖单苷(C₈G₁)和癸基-β-D-葡萄糖单苷(C10G₁)的临界胶束浓度(CMC)的测定。具体作法是以结晶紫(crystal violet,CV)为探针,测量一系列不同浓度的APG-CV水溶液体系的可见吸收光谱。其光谱特征是CV单体吸收峰598～609 nm和二聚体吸收峰538～569 nm叠合在一起。用高斯多峰拟合法实现了体系可见光谱吸收叠合峰的分峰、峰面积(积分吸光度)、频移及半高宽等光谱线型参数计算。单体和二聚体峰面积比(相对积分吸光度A₂/A₁)、频移(Δλ)及半高宽(w₁,w₂)对APG浓度图形在CMC处发生突变。首次发现可见吸收光谱线型参数半高宽对APG聚集行为敏感,并成功用于APG的CMC测量。     

Fluorescent Determination of Succinylcholine Chloride by Naphthalimide/ Stilbazolium Dye ⊂ CP5A

Succinylcholine Chloride (SCC), a short-acting neuromuscular relaxant, is non-fluorescent in aqueous solutions. This property makes it impossible to be determined by direct fluorescent method. Naphthalimide dye (NA) exhibits very strong fluorescence emissions in aqueous solution, after complexing with carboxylatopillar[5]arene (CP5A) in aqueous solutions, the fluorescent quenched intensity of complex was observed. On the contraty, stilbazolium dye (SA) exhibits weak fluorescence emissions in aqueous solution, after being included by CP5A, a fluorescence enhancement was observed. However, adding SCC to the NA? CP5A or SA? CP5A complex solution led to the recovery of the fluorescence intensity, in the meantime, the color of SA? CP5A solution changed from dark yellow to light yellow. The competitive supramolecular interaction between SCC, NA and SA for CP5A was studied by spectrofluorometry, ¹H NMR. Herein, a FID (fluorescence indicator displacement) system to detect SCC based on NA? CP5A and SA? CP5A complex was developed.     

吡喃酮型花色苷衍生物的制备、光谱特性及抗氧化活性研究

吡喃酮型花色苷衍生物是一类具有非氧鎓离子结构和内酯型吡喃环结构的新型多酚类化合物。本研究以植物花色苷为原料,通过羧基吡喃花色苷形成及微氧化等两步反应法,结合柱色谱分离纯化技术,制备高纯度的吡喃酮花色苷衍生物A (Oxovitisin A)标准品;高效液相色谱-光电二极管阵列检测器-串联质谱法(HPLC-DAD-ESI-MS/MS)分析鉴定出纯化后反应产物Oxovitisin A的纯度达99%以上。利用荧光光谱仪、紫外可见光谱仪及超微弱化学发光光谱仪研究了Oxovitisin A及其前体物质花色苷(锦葵素-3-葡萄糖苷,Mv-3-gluc)与羧基吡喃花色苷A(Vitisin A))的光谱特性、色泽稳定性及抗氧化活性。结果表明：Oxovitisin A在440 nm激发波长下有最大荧光峰,最大发射波长490 nm,而具有氧鎓离子结构的两种前体物质无荧光特性。紫外光谱结合LAB色泽空间表征参数显示Oxovitisin A在不同pH值条件下具有不同的结构稳定性和色泽稳定性。Mv-3-gluc,VitisinA和Oxovitisin A在不同体系中均表现出良好的抗氧化活性,清除超氧阴离子自由基的IC₅₀值分别为71.4,30.7和19 μg·mL-1(抗坏血酸28 μg·mL-1),清除羟自由基的IC₅₀值分别为1.68,3.524,2.854 μg·mL-1(抗坏血酸8.441 μg·mL-1),对双氧水清除率的IC₅₀值分别为1.311,0.4098和0.288 μg·mL-1(抗坏血酸3.265 μg·mL-1),表明Oxovitisin A清除自由基和抗氧化的能力均高于反应前体物Mv-3-gluc和VitisinA及抗坏血酸。