阻抑动力学荧光法测定鱼腥草中槲皮素的含量

在氨水介质中,反应温度为100 ℃;反应时间为6 min;以393 nm为激发波长,556 nm为发射波长,采用阻抑动力学荧光法测定鱼腥草中槲皮素的含量.方法的线性范围为0.01-0.1 mg/L,检出限为1.9×10-3 mg/L,用此方法可测定鱼腥草中槲皮素的含量,方法操作简便、灵敏度高.     

Characterization of steroidal saponins in crude extract from Dioscorea nipponica Makino by liquid chromatography tandem multi-stage mass spectrometry

The liquid chromatography-electrospray ionization-tandem multi-stage mass spectrometry (LC-ESI-MSⁿ) method was developed for the analyses and characterization of steroidal saponins in plant extract from the rhizome of Dioscorea nipponica Makino. The HPLC experiments were performed by means of a reversed-phase C₁₈ column and a binary mobile phase system consisting of water and acetonitrile under gradient elution conditions. Pseudoprotodioscin, methyl protodioscin and dioscin were identified by comparing the retention times, UV spectra and the fragmentation properties of [M − H]⁻ ions with the authentic standards. Four groups of steroidal saponin isomers possessed the [M − H]⁻ ions at m/z 1063, 1045, 901 and 1047, respectively, were observed during the LC-ESI(−)-MS analysis, and three groups of them except the pair of isomers with the [M − H]⁻ ions at m/z 1047 could be differentiated by LC-ESI(−)-MS³. Furthermore, the ESI-MSⁿ fragmentation behaviors of the [M + Li]⁺ ions of pseudoprotodioscin and methyl protodioscin have been investigated, and the observed information helped the structural elucidation of the more abundant isomer with the [M − H]⁻ ion at m/z 1047. As the result, a special sugar sequence of the saccharide chains was observed that not glucose but rhamnose might be connected with the hydroxyl group at C-3 position of the steroidal aglycone.     

Evaluation of the nanofibrillar structure of Dioscorea opposite extract for cell attachment

Dioscorea opposite has been widely used in traditional herbal medicine in the Far East, ameliorating symptoms ranging from abdominal swelling to pain. Previous studies have focused on understanding the chemical components that lead to the medicinal effects of the extract. In this study, we examined the nanostructures formed by the soluble and insoluble parts of the sticky excretion from the mucilaginous rhizome of Dioscorea opposite and evaluated their cellular response. Using atomic force microscopy, we found that the soluble extract of the excretion had the capacity to form a nanofibrillar scaffold composed of uniform ～10 nm nanofibers with a typical pore size of ～40 nm, while the insoluble extract formed some nanofibers without specific structure. Cellular response to the two types of nanostructures was tested by seeding with HeLa and MC3T3 cells. The observations suggested that the nanofibrillar scaffold formed from the soluble extract provided an excellent platform for HeLa cell attachment and growth and to a lesser degree for MC3T3 cells, while nanofibers from the insoluble extract displayed no cell attachment and growth. Further analysis by direct incubation of the soluble extract with growing cells indicated that components from the extract preferentially bound to HeLa cells, but not to MC3T3 cells, which might help explain the observed preference of HeLa cells on the nanofibrillar scaffold. The nanofibrillar scaffold created from the Dioscorea opposite extract and its ability to sustain the attachment of specific cell types demonstrate the potential for this natural nanomaterial in tissue engineering applications.     

反相高效液相色谱法测定穿山龙中的薯蓣皂甙元

利用超临界CO2萃取技术从穿山龙中提取薯蓣皂甙元,建立了反相高效液相色谱法测定穿山龙中薯蓣皂甙元的方法.采用Shim-pack CLC-ODS(150 mm×4.6 mm,5 μm)色谱柱,流动相为V(甲醇):V(水)=99:1,流速为1.0mL/min,UV检测波长为206 nm.在0.2～2.0 mg/mL范围内,薯蓣皂甙元峰面积与其质量浓度呈良好的线性关系,r=0.9997.进行了高、中、低3个不同浓度的加标回收率测定,相应的回收率分别为101.5%,99.88%,98.45%,平均值99.94%,RSD为1.7%.     

两种基体改进剂对山药中铅元素的测定比较

比较了磷酸二氢铵,氯化铵两种基体改进剂对石墨炉原子吸收光谱法(GF-AAS)测定了山药中铅元素的含量的研究。两种基体改进剂测得山药中的Pb含量分别为39.2μg.mL-1(氯化铵)、40.0μg.mL-1(磷酸二氢铵),回收率分别为106.5%、95.57%,RSD为均小于5%。最佳测定方法为:以磷酸二氢铵作为基体改进剂,灰化温度为1100℃,原子化温度为1900℃时,用氘灯校正背景进行测定。     

化学发光法测定几种怀山药的抗自由基活性

用不同溶剂将三种怀山药分成极性不同的部位 ,并用鲁米诺—H2 O2 —CuSO4 化学发光体系测定天然产物抗自由基活性的方法检测了这些部位的抗自由基活性 ,比较了不同品种怀山药的质量差异 ,所得结果与传统经验相吻合。