HBr-MgBr_(2)催化己糖二酸脱水环合制备2,5-呋喃二甲酸的研究

2,5-呋喃二甲酸(2,5-FDCA)是生物可降解塑料聚呋喃二甲酸乙二醇酯的聚合单体,未来需求量巨大。针对己糖二酸脱水环合制备2,5-呋喃二甲酸存在的收率低问题,开展了更高选择性催化体系的构建研究,成功筛选到了两个优良的催化体系:HBr-MgBr_(2)、HBr-LiBr。3%(质量)HBr-6%(质量)MgBr_(2)催化、120℃下反应2 h,D-葡萄糖二酸单钾盐脱水环合制备2,5-FDCA收率达到84.2%。当反应底物浓度低于5%(质量)以及水含量从3.3%富集到16.5%时,2,5-FDCA的摩尔收率未见明显下降,且都可维持在80%以上。测定了100-130℃温度范围内3%(质量)HBr-6%(质量)MgBr_(2)催化D-葡萄糖二酸单钾盐脱水环合制备2,5-FDCA动力学数据,采用一级反应动力学拟合得到2,5-FDCA的生成反应活化能为108.9 kJ/mol、副产物生成活化能为136.6 kJ/mol。研究工作对己糖二酸脱水环合制备2,5-FDCA路线的工业化具有积极推动作用。

己糖二酸脱水环合制备2,5-呋喃二甲酸反应路径探究

2,5-呋喃二甲酸(2,5-FDCA)是生物可降解聚呋喃二甲酸乙二醇酯(PEF)的单体,目前尚未形成廉价的制备技术,其中用己糖二酸脱水环合制备2,5-FDCA是一条具有发展潜力的路线。针对此路线中副产物定性不准确、反应路径研究不完善等问题,通过高效液相色谱、高分辨质谱、核磁共振和傅里叶变换红外光谱分析,开展了副产物定性工作,确定反应体系中的2个主要副产物为糠酸和3-羟基-6-羧基-2-吡喃酮(HOCA)。在硫酸催化下不同己糖二酸脱水环合的反应路径相似,半乳糖二酸易生成副产物HOCA,而葡萄糖二酸钙易生成主产物2,5-FDCA。结合文献报道,提出了己糖二酸脱水环合制备2,5-FDCA可能的完整反应路径。研究工作可为己糖二酸脱水环合制备2,5-FDCA的高效催化体系开发和工业化生产提供指导。

微波强化己糖二酸脱水环合制备2,5-呋喃二甲酸的研究

2,5-呋喃二甲酸(2,5-FDCA)是一种重要的生物质基聚酯单体。针对己糖二酸脱水环合制备2,5-FDCA中存在反应时间长的问题,在传统加热与微波加热的对比实验基础上,开展了HBr-MgBr_(2)催化下微波强化己糖二酸脱水环合制备2,5-FDCA的工艺研究。实验结果证实了微波的引入可在保证2,5-FDCA高收率的前提下显著提高己糖二酸脱水环合制备2,5-FDCA的反应速率,大大缩短反应时间。通过工艺优化,得到较佳的工艺条件:温度为110℃、催化剂质量分数w(HBr)=3%、w(MgBr_(2))=3%、微波强化反应15 min,2,5-FDCA收率可达75.0%。进一步考察了不同己糖二酸原料对微波强化脱水环合制备2,5-FDCA的影响,2,5-FDCA收率从高到低的次序为:葡萄糖二酸单钾盐>葡萄糖二酸钙>半乳糖二酸。研究工作将为己糖二酸路线制备2,5-FDCA的工业化进程起到一定的推动作用。

电位滴定法测定糖二酸钙的含量

目的:建立电位滴定法测定糖二酸钙的含量。方法:采用电位滴定法,用乙二胺四乙酸二钠滴定液(0.05mol/L)滴定,以钙复合电极用电位法指示终点。结果:电位突跃明显,方法可行。结论:电位滴定法有效排除主观因素对测定结果的影响,方法简便快速,准确度高,精密度好,可用于测定糖二酸钙的含量,同时本法可应用于各种样品中钙离子浓度测定。

HPLC法测定益母草中的5个己糖二酸和1个丁糖二酸类化合物

目的:建立测定益母草中5个己糖二酸和1个丁糖二酸类化合物含量的高效液相色谱法。方法:色谱条件为Agilent Poroshell 120 EC-C_(18)色谱柱(100 mm×4.6 mm,2.7μm),以0.1%甲酸水溶液-乙腈为流动相,梯度洗脱,柱温30℃,检测波长280 nm,流速0.8 mL·min^(-1)。结果:2-丁香酰基己糖二酸、2-阿魏酰基己糖二酸、2,4-二丁香酰基己糖二酸、3,4-二丁香酰基己糖二酸、2-丁香酰基苹果酸和2-阿魏酰基-4-丁香酰基己糖二酸等6个成分在各自的线性范围内线性关系良好(r≥0.9998),平均加样回收率为95.4%~100.1%,回收率的RSD≤3.9%,在30批不同产地的益母草药材中的平均含量为0.0278%~0.2353%,总含量为0.5248%~1.459%。结论:己糖二酸类成分是益母草中不容忽视的大类化学成分。

2,5-呋喃二甲酸的制备研究进展

在介绍2,5-呋喃二甲酸(2,5-FDCA)基本特性和原料来源的基础上,综述了以5-羟甲基糠醛(5-HMF)、糠醛/糠酸、呋喃、己糖二酸、果糖、二甘醇酸为起始原料制备2,5-FDCA的工艺的研究进展。此外,重点阐述了不同催化体系下5-HMF工艺路线的研究现状,认为以5-HMF为起始原料制备2,5-FDCA的工艺路线具有良好的工业化前景,而且该路线催化体系的筛选及工艺条件的优选有进一步研究的价值。

葡萄糖构型测定的改进

前 言 国内高等学校现在使用的有机化学教科书及参考资料中,对葡萄糖的构型测定,都采用了三个步骤:即(1)由低级糖合成高级糖。把D—阿拉伯糖和D—萄萄糖、D—甘露糖联系起来推导。(2)由糖的氧化和还原决定出D—葡萄糖和D—甘露糖的构型及L—古罗糖的构型。(3)再通过糖的降级反应决定出D—阿拉伯糖的构型。

龙眼果肉发酵红茶菌饮料

以龙眼果肉和茶糖水为原料,探讨了发酵温度、初始可溶性固形物和接种量等因素对龙眼果肉红茶菌发酵的影响,并以总酸、D-葡糖糖二酸1,4-内酯和D-葡萄糖二酸为响应值,利用响应面设计进行工艺优化,得出佳的发酵条件为:温度29.6℃,初始TSS为14.7°Brix,接种量为14.1%,发酵时间6 d,所得发酵液总酸含量为26.87 g/L,D-葡糖糖二酸1,4-内酯为5.51 g/L,D-葡萄糖二酸为18.01 g/L。

基于GC-MS的妇科千金胶囊挥发油治疗盆腔炎大鼠的血清代谢组学研究

目的基于气相色谱-质谱联用(GC-MS)技术探讨妇科千金胶囊挥发油对盆腔炎大鼠血清中内源性标志物的影响,并初步探讨其作用通路。方法采用金黄色葡萄球菌、大肠杆菌、解脲脲原体混合感染复制大鼠盆腔炎模型。将SD雌性大鼠随机分为正常对照组、假手术组、模型组、阳性药物组(康妇炎胶囊,0.42 g·kg^-1)和妇科千金胶囊挥发油组(6.3 mg·kg^-1),共5组,每组10只。每天灌胃1次,连续给药3周。模型复制结束后,应用GC-MS进行血清样品的分离和数据采集,以主成分分析(PCA)和正交偏最小二乘判别分析(OPLS-DA)法筛选出相关差异代谢物,对己鉴定结构的代谢标志物通过MetaboAnalyst数据库进行代谢通路分析。结果PCA结果显示,正常对照组、模型组和给药组大鼠血清代谢物发生显著变化。OPLS-DA结果显示,与正常对照组比较,模型组中发现9个显著差异的代谢标志物(VIP>1,|P(corr)|>0.6);与模型组比较,妇科千金胶囊挥发油组中有7个显著差异的代谢标志物,最终确定2个共有差异标志物为尿素、D-葡萄糖醛酸。通路分析显示,差异性代谢物主要与抗坏血酸和醛糖二酸代谢途径有关。结论妇科千金胶囊挥发油对盆腔炎性疾病的干预作用可能与抗坏血酸和醛糖二酸代谢有关。

Structure and Expression Analyses of a Gene Encoding Fructose-6-Phosphate, 2-Kinase/Fructose-2,6-Bisphosphatase from Maize

A full-length cDNA encoding fructose-6-phosphate, 2-kinase/fructose-2,6-bisphosphatase from maize (Zea mays L.) was cloned by the methods of reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE), and designated as mF2KP. The encoded protein is composed of two regions. Its COOH-terminal region is catalytic region and homologous to the enzymes from other eukaryotes; and its NH 2-terminal region is common and special region only in plant. A truncated fragment of mF2KP covering integrated catalytic region was expressed in Escherichia coli. The fusion protein had the activities of fructose-6-phosphate, 2-kinase as well as fructose-2,6-bisphosphatase. Northern blot showed that the transcript level of mF2KP in seedlings initiated from strong-vigor seeds is lower than that from weak-vigor seeds.

Deletion of 93 bp Far-upstream Fragment of Rice Cytosolic Fructose- 1, 6-Bisphosphatase Promoter Completely Alter Its Expression Pattern

The 1 195 bp 5′ flanking region of rice ( Oryza sativa L.) cytosolic fructose_1, 6_bisphosphatase (cyFBPase) can direct tissue, cell specific expression in transgenic rice. In order to identify sequence elements responsible for the regulation of mesophyll_specific expression, the 5′ flanking regions of -1 195 bp, -1 102 bp, -768 bp, and -644 bp upstream of the translation initiation ATG codon were fused to the reporter gene encoding β_glucuronidase (GUS) and transferred to rice via particle bombardment. Analysis of the 5′ promoter deletions identified that a 93 bp fragment between -1 195 bp and -1 102 bp is essential for directing mesophyll specific expression. High constitutive expression of GUS reporter gene was found in the -768 deletion lines and another two deletion series. These results indicate the great potential utility of the promoter in rice biotechnology.

Protective Effects of Sodium Magnesium Fructose Diphosphate on Brain Damage of Rats Subjected to Focal Cerebral Ischemia and Reperfusion

Objective: To study the effects of sodium magnesiusm fructose diphosphate(FDPM) on brain damage of rats after ischemia-reperfusion. Methods: Rats were subjected to cerebral ischemia-reperfusion induced by inserting a nylon thread into internal carotid artery to block the origin of middle cerebral artery and removing the thread later. FDPM (400 mg·kg -1), fructose-1,6-diphosphate (FDP, 400 mg·kg -1)and magnesium sulfate (MgSO 4, 30 mg·kg -1) were administrated 10 min after the onset of ischemia. Neurological scale, brain infarct area, Malondialdehyde(MDA) content and histopathological changes of brain tissue were studied. Results: FDPM decreased neurological scale, diminished brain infarct area, reduced MDA content and relieved histopathological change of rat brain tissue subjected to ischemia-reperfusion. These effects were more powerful than that of FDP or MgSO 4. Conclusions: It is suggested that FDPM markedly prevented rats against brain damage after cerebral ischemia-reperfusion, and its effect was better than that of FDP or MgSO 4.

Physiological Responses of Yixing Lily Leaf and Bulb to Drought Stress

[Objective]To explore an effective method for evaluating drought resistance of Yixing lily and provide a reference for selecting drought-resistant Yixing lily varieties. [Method]Through artificial simulation of drought stress environment,the changes of physiological indexes,such as content of proline,malonaldehyde,and reducing sugar in Yixing lily leaf and bulb were observed,when soil water content changed. [Result]The response to drought stress of the Yixing lily leaf was greater than that of the bulb,and the content of the proline and malonaldehyde was higher than that of the reducing sugar. [Conclusion]The leaves as an appropriate material for evaluation and analysis on drought resistance can better reflect the physiological responses of Yixing lily to drought stress. And the content of the malonaldehyde and that of proline are preferable indexes.

Protective Effects of Oral Fructose-1, 6-diphosphate on Liver Injury in Animal Models

Aim To investigate the effects of FDP on different liver injury models to explore the possibility of FDP used as an oral liver protective agent. Methods Chronic liver injury model in rats was induced by carbon tetrachloride （ CCl4 ） ; Acute liver injury model in mice was induced by aminogalactose （GAIN） or lipopolysaccharide （LPS）. Results In CCl4-induced chronic liver injury model, FDP （1 , 4 g·kg^-1·d^-1, q.d., for 10 weeks） significantly lowered ALT, AST,γ-glutamyl transpeptidase （γ-GT）, alkaline phosphatase （ALP）, and total bilirubin （T-BIL） in serum compared with vehicle; simultaneously it evidently elevated abnormal total protein （TP）, albumin （ALB） and total cholesterol （ T-CHO ） levels in serum; it also dose-dependently reduced hydroxyproline contents in hepatic tissue. 4 g·kg^-1·d^-1 of FDP apparently decreased incidence of hepatic cirrhosis, and alleviated pathological changes of liver tissue. In GaiN-induced model, 1.0 - 4. 0 g·kg^-1·d^-1 of FDP （ bid, for 3 d ） significantly lowered alanine aminotransferase （ ALT ） and aspartate aminotransferase （ AST ） levels in serum ; it also decreased liver coefficient. 4. 0 g·kg^-1·d^-1 of FDP significantly alleviated pathological changes of cell ultra-structures. In LPS-induced model, only high dose of FDP （4. 0 g·kg^-1·d^-1, bid, for 12 d） significantly decreased ALT level in serum. Conclusion This study first demonstrated the protective effect of oral FDP on chronic liver injury caused by CCl4, and confirmed its effect on acute liver injury at the same time, suggesting that Long-term oral FDP is efficacious against liver injury induced by different factors and can be used as an oral liver protective agent in clinic.

Isolation of a 1 195 bp 5′-Flanking Region of Rice Cytosolic Fructose-1,6-bisphosphatase and Analysis of Its Expression in Transgenic Rice

A genomic DNA fragment containing the 5'-upstream sequence and part of the open reading frame corresponding to the cytosolic fructose-1,6-bisphosphatase (cyFBPase) cDNA was isolated by Genome Walking. The 1 195 lip 5'-flanking region which started from the translation initiation ATG codon was fused to reporter gene encoding beta-glucuronidase (GUS) and stably transferred to rice via particle bombardment. Strong GUS activity was detected in leaves and leaf sheaths of transgenic rice, but not in culms and roots. Histochemical localization revealed that GUS expression was exclusively restricted to mesophyll cells in transgenic rice. Our results indicate that the 1 195 bp fragment contains all the cis-elements required for directing mesophyll-specific expression pattern in rice.

NUCLEOTIDE SEQUENCE OF RIBULOSE 1,5 BISPHOSPHATE CARBOXYLASE/OXYGENASE LARGE SUBUNIT GENE FROM MILLET(SETARIA ITALICA) *

The 3.0 kb BglⅡ+XbaⅠrestriction fragment of millet(Setaria italica) chloroplast genome containing rbcL gene had been cloned into pBluescript SK (-) vector, then the restriction map and the 1990 bp complete nucleotide sequence was determined. The 1431 bp coding region of the gene consists of 476 amino acid residues with a predicted molecular weight of 52679 D. The 389 bp 5′ upstream region has the putative -10 box, -35 box and SD sequence, similar to that of procaryotes. The 170 bp 3′ downstream region contains three stem loop structures. Comparison of the rbcL gene sequences between C 4 plants and several C 3 plants reveals no difference in the coding region, promoter and 3′ downstream region. It might be concluded that the rbcL gene sequence has no relation with its cell specific expression.

Protective Effect of Tetrandrine and Fructose-1,6-diphos phate on the Model of Focal Cerebral Ischemia in Rats

The effect of tetrandrine (Tet) on the infarction area and volume of rat brain induced by middle cerebral artery occlusion (MCAO) was investigated. The treatment with Tet 7.5, 12.0 or 15.0 mg·kg 1 , or with fructose 1,6 diphosphate (FDP) 200 and 350 mg·kg 1 ip immediately after MCAO, respectively, significantly reduced the infarction area and volume in a dose dependent manner. MK801 and FDP also displayed a protective effect on brain ischemia. A combination of Tet and FDP administered immediately after MCAO, produced a more potent protective effect than those treated with Tet or FDP alone. When Tet or FDP was administered 1 h and 2 h after MCAO, respectively, they could still significantly reduce the infarction area and volume of brain tissue. But, there was no significant protective effect when these two compounds were given 3 h after MCAO.

Effects of fructose-1,6-diphosphate on concentration of calcium and activities of sarcoplosnic Ca^(2+)-ATPase in cardiomyocytes of Adriamycin-treated rats

Objective: To observe the effects of fructose-1,6-diphosphate (FDP) on serum levels of cardiac troponin 1 (cTnl) and creatine kinase-MB (CK-MB), as well as the concentration of calcium in cardiomyocytes (Myo[Ca2+]) and activity of sarcoplosnic Ca2+-ATPase (SRCa2+-ATPase) in Adriamycin (ADR)-treated rats. Methods: Rats were intraperitoneally injected with ADR (2.5 mg/kg every other day for 6 times) and then with different dosages of FDP (every other day for twenty-one times). Bi-antibodies sandwich Enzyme linked immune absorption assay (ELISA) was performed to detect serum level of cTnl. CK-MB was detected by monoclonal antibody, Myo[Ca2+] was detected by fluorescent spectrophotometry and the activity of SRCa2+-ATPase was detected by inorganic phosphate method. Results: FDP (300, 600, 1200 mg/kg) significantly reduced the serum levels of cTnl and CK-MB, while at the same time decreased calcium concentration and increased SRCa2+-ATPase activity in cardiomyocytes of ADR-treated rats (P<0.01). Conclusions: FDP might alleviate the cardiotoxic effects induced by ADR through decreasing calcium level as well as increasing SRCa2+-ATPase activity in cardiomyocytes.

Cloning and Sequence Analysis of rbcS Gene of Wild Barley (Hordeum brevisubulatum) under Salt Stress

[Objective] The aim was to study the cloning and sequence analysis of rbcS gene of wild barley under salt stress. [Method] The tender leaf blade of wild barley under salt stress was taken as the experimental material. The primers were designed according to the homology of rbcS gene sequences of wheat and barely in Genbank; then PCR amplification,recovery,ligation,transformation and sequencing of rbcS gene were carried out. [Result] Two rbcS genes including rbcS1 and rbcS2 with the length of 1 252 and 908 bp respectively were cloned from the barely genome. rbcS1 and rbcS2 were both composed by two exons and one intron. The exons length of the two genes was the same of 525 bp,encoding 174 amino acids,and the homology between them was 96%; however,the intron length of rbcS1 and rbcS2 was 448 and 107 bp respectively.

Structural sensitivity of heterogeneous catalysts for sustainable chemical synthesis of gluconic acid from glucose

Gluconic acid and its derivatives have been widely used in the food and pharmaceutical industries. Conventional processes that involve the conversion of glucose into gluconic acid via fermentation present several technological shortcomings as they involve energy-intensive wastewater treatment and complex enzyme separation. Greener oxidation processes over heterogeneous metal catalysts have attracted increasing attention worldwide. Au-, Pt-and Pd-based heterogeneous catalysts have been extensively used for the chemical oxidation of glucose to gluconic acid. Bimetallic catalysts synthesized by adding either noble or inexpensive metals have also presented excellent performance for the oxidations of glucose. In particular, particle size, which has been recognized as the most important factor that affect catalytic performances, could be rationally tuned by changing the types of support and ligand as well as the synthesis conditions. In this perspective review, we summarize and critically discuss the recent advances in the structural design of mono-and bimetallic catalysts for the oxidation of glucose in aqueous media. Furthermore, the challenges of developing catalysts for the green synthesis of gluconic acid have been highlighted. This review provides alternative insights for designing effective catalytic materials for the catalytic oxidation of bio-derived oxygenates over heterogeneous catalysts.