新型生物黏附性材料巯基壳聚糖的合成与表征

巯基聚合物利用二硫键的形成, 以共价键黏附于黏膜表面, 可以延长药物在黏膜上的滞留时间, 有利于药物分子的吸收. 本文合成了一种新型巯基聚合物——N-乙酰基-L-半胱氨酸-g-壳聚糖(CS-NAC), 并进行了表征, 同时对材料的溶胀度、黏附性和细胞毒性进行了测试. 结果表明, 这种巯基聚合物具有较高的巯基含量, 最高可达到589.3 μmol/g; 具有快速的溶胀性能; 黏附性显著增强, 黏附时间和黏附力分别是壳聚糖的30和3倍; 无明显的细胞毒性. 因此, CS-NAC是一种很有应用前景的生物黏附性材料.     

Synthesis of thia-Michael-Type Adducts between Naphthoquinones and N-Acetyl-L-Cysteine and Their Biological Activity

A series of naphthoquinones, namely, 1,4-naphthoquinone, menadione, plumbagin, juglone, naphthazarin, and lawsone, were reacted with N-acetyl-L-cysteine, and except for lawsone, which did not react, the related adducts were obtained. After the tuning of the solvent and reaction conditions, the reaction products were isolated as almost pure from the complex reaction mixture via simple filtration and were fully characterized. Therefore, the aim of this work was to evaluate whether the antitumor activity of new compounds of 1,4-naphthoquinone derivatives leads to an increase in ROS in tumor cell lines of cervical carcinoma (HeLa), neuroblastoma (SH-SY5Y), and osteosarcoma (SaOS2, U2OS) and in normal dermal fibroblast (HDFa). The MTT assay was used to assay cell viability, the DCF-DA fluorescent probe to evaluate ROS induction, and cell-cycle analysis to measure the antiproliferative effect. Compounds 8, 9, and 12 showed a certain degree of cytotoxicity towards all the malignant cell lines tested, while compound 11 showed biological activity at higher IC₅₀ values. Compounds 8 and 11 induced increases in ROS generation after 1 h of exposure, while after 48 h of treatment, only 8 induced an increase in ROS formation in HeLa cells. Cell-cycle analysis showed that compound 8 caused an increase in the number of G0/G1-phase cells in the HeLa experiment, while for the U2OS and SH-SY5Y cell lines, it led to an accumulation of S-phase cells. Therefore, these novel 1,4-naphthoquinone derivatives may be useful as antitumoral agents in the treatment of different cancers.     

薄层色谱法对N-乙酰-L-半胱氨酸工艺流程诊断

建立了用薄层层析和薄层扫描法对N-乙酰-L-半胱氨酸合成进行流程诊断的方法.采用硅胶G板,以正丁醇-醋酸-水(4.5:1.5:1)为展开剂,单波长直线扫描,扫描波长λ=700nm.对合成反应的初始阶段、反应中、反应后取样样品进行定性和定量检测.原料在反应滴加后的初始阶段转化率达到97.08%,说明水相合成法较为合理,有效地抑制了L-半胱氨酸的氧化.设计的流程诊断法对N-乙酰-L-半胱氨酸和半胱氨酸盐酸盐的线性范围分别为15.1～36.5 mg/mL、1.5～3.1 mg/mL.平均回收率分别为99.93%～100.05%、99.94%～100.10%.RSD分别为0.32%～0.34%、0.31%～0.34%.该方法可靠、简便易行,有利于反应流程诊断控制.     

CdS量子点的合成及其光学性能

以硝酸镉和硫代乙酰胺为原料,以N-乙酰-L-半胱氨酸(NAC)为稳定剂,在水溶液中合成了Cd S量子点(Cd S QDs)。通过考察稳定剂的配比、反应温度、反应时间、p H和搅拌时间对Cd S QDs的影响,研究Cd S QDs的光学性能。结果表明:当n(Cd2+)/n(NAC)=2/1,p H=7,搅拌10 min,于80℃反应2 h制得的Cd S QDS荧光性能较好。     

柱前手性衍生色谱法拆分DL—氨基酸时流动相的影响

本文利用邻苯二甲醛和Ｎ－乙酰－Ｌ－半胱氨酸作柱前手性衍生化试剂，经反相高效液相色谱法拆分ＤＬ－氨基酸对映体，研究了流动相组成对出峰顺序和分离效果的影响。     

柱前衍生高效液相色谱法测定茶叶中茶氨酸及γ-氨基丁酸含量

对茶叶中的茶氨酸和γ-氨基丁酸(GABA)建立了柱前衍生方法,并利用高效液相色谱法(HPLC)对衍生物进行了测定。采用邻苯二甲醛(OPA)及N-乙酰-L-半胱氨酸(NAC)为衍生试剂,考察了脯氨酸(Pro)、茶多酚(Tp)及维生素C(Vc)等对衍生体系的影响,并对色谱分离条件进行了优化。结果表明,茶氨酸与GABA衍生物在色谱柱上的保留行为与分离效率主要受流动相pH及缓冲盐浓度的影响;Pro、Tp及Vc对茶氨酸的衍生产率影响较小。而Vc可以提高GABA检测的灵敏度,并能稳定衍生用储备液。GABA与茶氨酸衍生后的方法检出限(LOD)分别为3.01×10~5mmol/L和7.98×10~5mmol/L;定量限(LOQ)分别为9.99×10~5mmol/L和2.658×10~4mmol/L;线性范围分别为0.01～0.4 mmol/L(相关系数为0.996)和0.05～0.8 mmol/L(相关系数为0.995);方法的回收率分别为99.29%～119.60%和93.18%～141.06%(除本身含茶氨酸量高的绿茶中回收率为62.88%外)。这说明经优化的柱前衍生-高效液相色谱体系可用于茶叶中两种特征性氨基酸的测定。