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排序方式: 共有57条查询结果,搜索用时 15 毫秒
1.
在酸性介质中对香英兰素与儿茶素的显色反应进行了研究,改进了反应条件,以506nm为测定波长,测定TP口含片中儿茶素的含量,线性范围7.58μg~53.05μg(r=0.9998),回收率97.97%,RSD1.85%,认为改良法简便,灵敏,口含片辅料无干扰,可用于原料的药和制剂的含量分析。 相似文献
2.
《Journal of labelled compounds & radiopharmaceuticals》2004,47(4):209-216
[Uniformly ring‐14C]‐labelled 4‐hydroxybenzaldehyde, vanillin, and protocatechualdehyde were synthesized from [14C]‐labelled phenol, guaiacol, and catechol with methyl dichloromethyl sulfide (CH3SCHCl2) under Friedel–Crafts alkylation conditions in dichloromethane at ?78°C for 5 min (in the case of phenol and guaiacol) or at ?20°C for 1 min (in the case of catechol), by rapid addition of SnCl4 to mixtures of the phenolic compound and CH3SCHCl2, followed by hydrolysis with HCl. Regioselective formylation (para to the –OH group) was achieved. The conversion rates were 96, 81, and 88% for 4‐hydroxybenzaldehyde, vanillin, and protocatechualdehyde, respectively, and the yields of the recovered products after work‐up amounted to 88, 75, and 83%, respectively. In the case of guaiacol, 17% of isovanillin was obtained as by‐product. It was found that the presence of water or ethyl acetate in the reaction mixture, at a molar ratio of 60:1 (water:guaiacol) or 120:1 (ethyl acetate:guaiacol), had little influence on the yields under the reaction conditions. Factors influencing the yields are discussed in the study. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
3.
Khan Hashim Ali Muhammad Mohsin Ansari Fawad Ali Shah Fakhar Ud Din Muhammad Abdul Basit 《Journal of microencapsulation》2019,36(1):10-20
The study was aimed to prepare a co-amorphous system of valsartan (VAL) with vanillin (VAN) for improving its solubility and dissolution followed by its confinement in mesoporous silica particles (MSPs) to stabilise the co-amorphous system and prevent its recrystallization. Amorphous VAL and VAN were obtained through quench-cooling and VAL/VAN binary co-amorphous system (VAL/VAN-CAS) was prepared through solvent evaporation technique. The particle size and morphology of VAL/VAN-CAS-MSPs were studied using scanning electron microscopy (SEM) and solid-state characterisation was performed by differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). The in vitro dissolution was investigated by dialysis bag diffusion method. SEM analysis revealed irregular shaped VAL/VAN-CAS-MSPs with a size range of 5–25?μm, while outcomes of DSC and XRPD confirmed the formation of VAL/VAN-CAS. The in vitro dissolution profiles demonstrated a significantly increased dissolution in first 60?minutes from VAL/VAN-CAS (~68%) and VAL/VAN-CAS-MSPs (~76%) compared to powder VAL (~25%). 相似文献
4.
目的:通过观察辐射对高尔基体形态的影响,确定香兰素衍生物VND3207对受照细胞高尔基体的防护作用。方法采用免疫荧光技术检测放射损伤细胞中高尔基体弥散现象并统计弥散面积,检测细胞周期变化,分析细胞存活率,同时对高尔基体蛋白的表达水平进行检测。结果免疫荧光检测结果显示,照射后高尔基体的弥散面积增加,具有一定的剂量效应和时间效应;VND3207能减轻γ射线对高尔基体的损伤,其表现为与未加药组相比,在抑制不同剂量照射后可使高尔基体弥散面积增加;细胞周期测定结果显示,4 Gy γ线照射后G2/M期阻滞峰值约出现在12 h后;免疫印迹结果显示DNA损伤引起的G2/M期阻滞也在12 h后解除;而高尔基体弥散在细胞周期阻滞解除后12和24 h仍然存在;平板克隆结果显示,VND3207促进了受照细胞的存活。结论放射损伤能引起剂量依赖性高尔基体弥散效应,且这种弥散与DNA损伤诱导的周期阻滞无关,VND3207对放射损伤引起的高尔基体弥散有一定的抑制作用,可能与受照细胞受到保护有关。 相似文献
5.
目的建立同时测定天麻饮片中天麻素、对羟基苯甲醇、香荚兰醇、对羟基苯甲醛、香荚兰醛、巴利森苷B、巴利森苷C、巴利森苷A 8种成分的高效液相色谱-质谱(HPLC-MS)分析方法。方法采用Agilent 1220高效液相系统,Hypersil C18色谱柱(250 mm×4.6 mm,5μm);流动相为0.5%醋酸水溶液(A)-0.5%醋酸甲醇溶液(B),梯度洗脱:0~10 min,98%A;10~60 min,98%~60%A;60~75 min,60%A;分析时间75 min;体积流量0.8 m L/min;柱温30℃;进样量20μL。采用电喷雾离子源进行负离子模式监测,多反应监测模式用于定量分析,源喷射电压为-4 500 V,离子源温度为550℃。结果测定的8种成分在线性范围内均具有良好的线性关系(r≥0.999 2);平均回收率在94.51%~102.70%,RSD3.50%。在不同产地的天麻饮片中,8种成分的量差异较大。其中,3种巴利森苷类成分的量较高,香荚兰醇和香荚兰醛的量均较低。结论建立的测定方法分离效果及重复性好,且快速、简便,可作为天麻饮片的质量控制方法。 相似文献
6.
Chitosan as a natural polysaccharide derived from chitin of arthropods like shrimp and crab, attracts much interest due to its inherent properties, especially for application in biomedical materials. Presently, biodegradable and biocompatible chitosan nanoparticles are attractive for drug delivery. However, some physicochemical characteristics of chitosan nanoparticles still need to be further improved in practice. In this work, chitosan nanoparticles were produced by crosslinking chitosan with 3-methoxy-4-hydroxybenzaldehyde (vanillin) through a Schiff reaction. Chitosan nanoparticles were 200–250?nm in diameter with smooth surface and were negatively charged with a zeta potential of???17.4?mV in neutral solution. Efficient drug loading and drug encapsulation were achieved using 5-fluorouracil as a model of hydrophilic drug. Drug release from the nanoparticles was constant and controllable. The in vitro cytotoxicity against HT-29 cells and cellular uptake of the chitosan nanoparticles were evaluated by methyl thiazolyl tetrazolium method, confocal laser scanning microscope and flow cytometer, respectively. The results indicate that the chitosan nanoparticles crosslinked with vanillin are a promising vehicle for the delivery of anticancer drugs. 相似文献
7.
Esther Oder Martin K. Safo Osheiza Abdulmalik Gregory J. Kato 《British journal of haematology》2016,175(1):24-30
The hallmark of sickle cell disease is the polymerization of sickle haemoglobin due to a point mutation in the β‐globin gene (HBB). Under low oxygen saturation, sickle haemoglobin assumes the tense (T‐state) deoxygenated conformation that can form polymers, leading to rigid erythrocytes with impaired blood vessel transit, compounded or initiated by adhesion of erythrocytes to endothelium, neutrophils and platelets. This process results in vessel occlusion and ischaemia, with consequent acute pain, chronic organ damage, morbidity and mortality. Pharmacological agents that stabilize the higher oxygen affinity relaxed state (R‐state) and/or destabilize the lower oxygen affinity T‐state of haemoglobin have the potential to delay the sickling of circulating red cells by slowing polymerization kinetics. Relevant classes of agents include aromatic aldehydes, thiol derivatives, isothiocyanates and acyl salicylates derivatives. The aromatic aldehyde, 5‐hydroxymethylfurfural (5‐HMF) increases oxygen affinity of sickle haemoglobin and reduces hypoxia‐induced sickling in vitro and protects sickle cell mice from effects of hypoxia. It has completed pre‐clinical testing and has entered clinical trials as treatment for sickle cell disease. A related molecule, GBT440, has shown R‐state stabilization and increased oxygen affinity in preclinical testing. Allosteric modifiers of haemoglobin as direct anti‐sickling agents target the fundamental pathophysiological mechanism of sickle cell disease. 相似文献
8.
目的 分析中国海南与巴布亚新几内亚所产香荚兰商品荚乙醇提取物中化学成分的差异并测定香草醛的量.方法 对不同样品处理方法进行比较,采用GC-MS分析法,利用Agilent DB-5MS弹性石英毛细管柱(30 m×0.32 mm,0.25 μm),在初始温度为60℃,保持1 min,以10℃/min升至260℃,保持6 min,再以6℃/min升至290℃,保持8 min;载气为氦气的条件下,对比两产地乙醇提取物的差异.结果 两产地所产香荧兰商品荚乙醇提取物中分别鉴定出34和32种化合物,其中共有化合物18种.香草醛在香荚兰商品荚中的相对质量分数较高,定量测定结果表明,在质量浓度0.04~1.10 mg/mL内与峰面积呈良好的线性关系(r=0.999 8,n=5);回收率为100.05%,RSD为1.88%.结论 本方法能快速、简便、高效地检测出香荚兰商品荚乙醇提取物的化学成分,并且在香草醛的定量测定中具有稳定、可重复的特点. 相似文献
9.
Altered hepatic mRNA expression of immune response‐associated DNA damage in mice liver induced by potassium bromate: Protective role of vanillin
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Hajer Ben Saad Dorra Driss Ibtissem Ben Amara Ons Boudawara Tahia Boudawara Samia Ellouz Chaabouni Khaled Mounir Zeghal Ahmed Hakim 《Environmental toxicology》2016,31(12):1796-1807
Chronic exposure to potassium bromate (KBrO3), a toxic halogen existing widely in the environment, environment through contaminated drinking water, has become a global problem of public health. The present study investigates the protective role of vanillin against KBrO3 induced oxidative stress, distruption in inflammatory cytokines expression, DNA damage, and histopathological changes. Adult mice were exposed orally to KBrO3 (2g/L of drinking water) for 2 weeks The co‐administration of vanillin to the KBrO3‐treated mice significantly prevented the plasma transaminases increase in. Furthermore, it inhibited hepatic lipid peroxidation (malondialdehyde), advanced oxidation protein product (AOPP) and protein carbonyl (PCO) formation and attenuated the KBrO3‐mediated depletion of enzymatic and non enzymatic antioxidants catalase, superoxide dismutase, and glutathione peroxidase activities and glutathione level in the liver. In addition, vanillin markedly attenuated the expression levels of proinflammatory cytokines, including tumor necrosis factor‐α, interleukin‐1β, interleukin‐6, and COX2 and prevented KBrO3‐induced hepatic cell alteration and necrosis, as indicated by histopathological data. DNA damage, as assessed by the alkaline comet assay, was also found to be low in the co‐treated group. Thus, these findings show that vanillin acts as potent chemopreventive agent against KBrO3‐mediated liver oxidative stress and genotoxicity through its antioxidant properties. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1796–1807, 2016. 相似文献
10.
香兰醛改性壳聚糖对金属离子的吸附机理 总被引:1,自引:0,他引:1
目的;研究香兰醛改性的壳聚糖(V-CTS)对金属离子的吸附机理,方法:测定V-CTS对金属离子的等温吸附线,并用FT-IR法研究V-CTS与离子形成的配合物的结构特征。结果:V-CST对Cd^2+、Zn^2+的吸附符合Langmuir及Freundlich公式,对Pb^2+的吸附不符合上述公式。吸附剂分子中多种官能团参与了配位。结论:V-CTS对Cd^2+、Zn^2+和Pb^2+的吸附以化学吸附为 相似文献