RP-HPLC法测定不同生长年份栽培藏木香主要活性成分含量

采用RP-HPLC法测定不同生长年份栽培藏木香主要活性成分土木香内酯和异土木香内酯含量,并对其含量进行比较。异土木香内酯和土木香内酯质量浓度在9.34~46.67μg/mL,7.34~36.67μg/mL范围内与色谱峰面积均呈良好的线形关系,平均回收率分别为100.61%和100.34%,RSD为2.11%和1.89%。方法可用于栽培藏木香主要活性成分含量测定。测定结果表明,异土木香内酯含量高于土木香内酯,总量随生长年份不断增高,并主要存在于根部,茎叶未检测到。     

川芎和抚芎的多糖和重金属含量分析

为提高川芎质量,控制重金属含量,采用苯酚-硫酸法测定了川芎和抚芎中的多糖含量,采用原子吸收光谱法测定了其中重金属含量。结果表明,川芎和抚芎多糖含量分别为(25.35±0.23)和(23.52±0.51)mg/g,重金属铅、汞、镉的含量分别为(1.28±0.12)、(0.21±0.22)、(0.25±0.11)μg/g和(2.24±0.21)、(0.16±0.22)、(0.35±0.20)μg/g。苯酚-硫酸法简单、快速、准确度高,重现性好,用于测定川芎和抚芎多糖结果可靠。川芎汞含量有一定超标,抚芎镉含量超标,应引起注意。     

高效液相色谱法快速测定烟丝水提取液中尼古丁和可天宁生物碱

建立了烟丝水提取液中尼古丁和可天宁生物碱的高效液相色谱(HPLC)快速检测方法。色谱柱为ZORBAX Eclipse Plus C18柱,流动相为甲醇-0.02 mol/L KH2PO4-三乙胺(体积比10∶90∶0.05,pH=3.2)。将该方法用于不同品牌香烟烟丝中尼古丁和可天宁的含量分析,结果显示黄山、白沙、万宝路和广东湛江廉江烟丝厂烟丝中尼古丁生物碱含量分别为10.59±0.77 mg/g、13.53±0.38 mg/g、10.82±0.41mg/g和10.89±0.92mg/g;可天宁生物碱含量分别为0.53±0.04mg/g、0.38±0.02mg/g、0.24±0.01mg/g和0.51±0.001mg/g。     

超高效液相色谱-串联质谱法同时检测植物叶片中吲哚-3-乙酸及其3种氧化产物

以玉米叶片为供试材料,建立了同时测定植物体内吲哚-3-乙酸(IAA)及其3种氧化产物吲哚-3-甲醇(ICI)、吲哚-3-甲醛(ICA)、吲哚-3-羧酸(IFA)含量的超高效液相色谱-串联质谱(UPLC-MS/MS)方法。结果表明,该方法对IAA及其3种氧化产物检测的线性、精密度和重复性较好,灵敏度较高,4种化合物的检出限为0.002~1.63μg/kg,定量下限为0.007~5.43μg/kg;方法的加标回收率为89.5%~95.3%,相对标准偏差为2.3%~5.1%。玉米叶片的实际测定结果表明,IAA,ICI,ICA和IFA的含量分别为(196.25±7.10),(26.21±2.13),(18.65±2.02),(13.62±2.06)μg/kg。该方法已成功应用于小麦、豌豆、硬毛刺苞菊叶片的测定,通用性较好。     

高效液相色谱法测定香铃草子中还原型谷胱甘肽和总巯基含量

以5,5′-二硫双-2-硝基苯甲酸为衍生化试剂,使用细胞破壁、衍生化为一体的同步衍生化法,采用高效液相色谱法测定了香铃草子中还原型谷胱甘肽(GSH)和总巯基(-SH)含量。结果表明:香铃草子中GSH和总巯基含量均值分别为4.07μmol/g和6.06μmol/g。总巯基含量中扣除GSH含量大致为巯基蛋白含量,达1.99μmol/g,说明香玲草子富含GSH和巯基蛋白。优化色谱条件下GSH和总疏基的回收率分别为100.43%和101.79%,检测限分别为5.31μmol/L和6.18μmol/L。     

UHPLC测定盐酸氟西汀原料药中甲醛及其测量不确定度评定

采用超快速液相色谱(UHPLC)建立了快速测定盐酸氟西汀原料药中甲醛残留的方法。样品经50%乙腈-水溶液提取,酸性条件下与2,4-二硝基苯肼发生衍生化反应,采用超快速液相色谱仪外标法测定盐酸氟西汀原料药中甲醛的含量,添加量为5～20μg/g时,平均回收率为96.8%～99.0%。评估了测量方法的不确定度。盐酸氟西汀原料药中甲醛含量的测量结果表示为(7.40±0.46)μg/g,k=2。方法适用于盐酸氟西汀中甲醛的快速检测。     

高效液相色谱法测定黄蜀葵花总黄酮胶囊中的金丝桃苷和槲皮素-3'-葡萄糖苷

建立高效液相色谱法测定黄蜀葵花总黄酮中金丝桃苷和槲皮素-3’-葡萄糖苷的含量。以乙腈–0.5%磷酸水溶液(22∶78)为流动相,流量为1.0 mL/min,柱温为30℃,检测波长为360 nm。金丝桃苷和槲皮素-3’-葡萄糖苷的质量浓度分别在12.232～73.392μg/mL,11.044～66.264μg/mL范围内与色谱峰面积呈良好的线性关系,相关系数均为0.999 9,检出限分别为200,180 ng/g。样品加标回收率分别为99.73%,100.78%,测定结果的相对标准偏差分别为0.86%,1.48%(n=6)。该方法操作简单、快速,结果准确,重现性好,可为黄蜀葵花总黄酮胶囊的质量控制提供依据。     

HPLC-DAD-ESI/MS~n-DPPH在线筛选与鉴别丹参和康定鼠尾草中抗氧化活性成分

本研究建立了在线高效液相色谱-质谱-二苯基三硝基苯肼(HPLC-DAD-ESI/MSn-DPPH)快速筛选和鉴别丹参和康定鼠尾草中抗氧化活性成分和含量的方法。经液相色谱、质谱和文献报道综合分析鉴定出丹参和康定鼠尾草中的3种抗氧化活性化合物,分别为咖啡酸、异迷迭香酸苷和迷迭香酸。比较了热回流、超声辅助提取和快速溶剂萃取的提取效果,并对色谱条件进行优化。在优化条件下,这3种化合物均可有效分离,并在1.7~35.3μg/m L范围内线性关系良好,相关系数为0.999 5~0.999 8,检出限为0.05~1.85μg/m L,定量下限为0.18~6.16μg/m L,平均回收率为96.6%~97.2%,相对标准偏差为1.1%~1.3%。运用该方法测定丹参和鼠尾草样品中这3个化合物的含量分别为:咖啡酸0.303,0.254 mg/g;异迷迭香酸苷1.019,1.401 mg/g;迷迭香酸17.279,8.104 mg/g。本方法简便、快速、准确、重现性好,适用于从复杂天然产物中快速筛选与鉴别抗氧化活性成分。     

酶联免疫法测定人碱性成纤维细胞生长因子脂质体的包封率

建立了一种灵敏的定量检测人碱性成纤维细胞生长因子(hbFGF)脂质体中hbFGF含量的酶联免疫(ELISA)方法,应用于测定hbFGF脂质体的包封率。通过用hbFGF标准品溶液包被酶标板,加入特异性的鼠抗人hbFGF抗体(一抗)和山羊抗鼠IgG(二抗),采用多因素棋盘滴定方法确定最佳实验条件为:一抗浓度200μg/L,二抗浓度50μg/L。本方法的检出限为0.86μg/L,工作浓度范围1.0~10μg/L,批内RSD为3.95%~4.27%,批间RSD为4.19%~7.21%,不同操作者批内和批间的RSD分别为6.21%和9.12%,可重复性良好。本方法测定hbFGF脂质体超滤液和氯仿提取液中hbFGF含量分别为(3.325±0.193)μg/L和(18.454±1.063)μg/L,组内RSD分别为4.69%和4.52%。hbFGF脂质体包封率为82.06%。本方法特异性高、重复性好、快速、简便,可用于hbFGF脂质体包封率及其它含hbFGF制剂的含量测定。     

基于四通道色谱分离仪快速检测土壤中的低浓度多氯联苯

为快速准确检测土壤中21种低浓度多氯联苯(PCBs)的含量,建立了以丙酮-正己烷(1:1,V/V)为萃取剂超声提取,四通道色谱分离仪对提取液进行分离和净化的前处理方法。采用氮吹法将前处理的样品浓缩至50μL以下,以PCB 54作为内标,利用气相色谱-63Ni微电子捕获检测器(GC-ECD)进行定量测定。土壤中21种PCBs的回收率为68.6%~102.3%,相对标准偏差为2.2%~9.9%,方法检出限为1.21~4.67μg/kg。采用所建方法对长江三角洲地区经长期植物修复后的PCBs污染土壤和无污染的农田土壤进行检测,结果显示,修复后的土壤PCBs总量为99.88±3.97μg/kg,无污染农田土壤PCBs总量为69.01±2.19μg/kg。     

Total synthesis of naturally occurring 5,6,7- and 5,7,8-trioxygenated coumarins

The synthesis of five naturally occurring polyoxygenated coumarins is described. It concerns two 5,6,7-trioxygenated coumarins, i.e., 6-hydroxy-5,7-dimethoxycoumarin (fraxinol) 1 and 5,6,7-trimethoxycoumarin 2, and three 5,7,8-trioxygenated coumarins, i.e., 8-hydroxy-5,7-dimethoxycoumarin (leptodactylone) 3, 5,7,8-trimethoxycoumarin 4 and 8-(3-methyl-2-butenyloxy)-5,7-dimethoxycoumarin (artanin) 5. Key feature of the synthetic pathway is the synthesis of suitable tetraoxygenated benzaldehydes, which are then converted to the corresponding coumarins via a Wittig reaction.     

ISOLATION and CHARACTERIZATION OF THE PHOTOADDUCTS OF 5,7-DIMETHOXYCOUMARIN and ADENOSINE

The isolation and structural characterization of the photoadducts of 5,7-dimethoxycoumarin and adenosine are described. Two of the major photoadducts were isolated by preparative column chromatography and reverse-phase high performance liquid chromatography. Structure of the products was determined by UV, FT-IR, mass spectrometry, ¹H NMR and ¹³C NMR studies, including the homonuclear decoupling, COSY method and DEPT experiments. The photoadducts were not C₄-cycloadducts but simple addition products in contrast to pyrimidine base adducts. Covalent bonds were formed between the carbon-3 or carbon-4 of the pyrone ring of 5,7-dimethoxycoumarin and the carbon-5'of ribose ring in adenosine.     

PHOTOCYCLOADDITION OF 5,7-DIMETHOXYCOUMARIN TO THYMINE

Abstract— C₄-_-Photocycloaddition of 5,7-dimethoxycoumarin (DMC) to thymine (λ≥ 300 nm) was studied in dioxane-water solution, in aqueous frozen state, and solid film state. The major product was isolated and characterized by physical methods. Elemental analysis data, spectral analyses, and photo-splitting of the product indicate the product to be a 1:l C₄-_-cycloadduct of DMC and thymine.     

UPLC-Q-TOF-MS analysis of non-volatile migrants from new active packaging materials

Ultra-performance liquid chromatography (UPLC) coupled to mass spectrometry (MS) is a useful tool in the analysis of non-volatile compounds, and the use of a quadrupole-time-of-flight (Q-TOF) mass analyzer allows a high sensitivity and accuracy when acquiring full fragment mode, providing a high assurance of correct identification of unknown compounds. In this work, UPLC-Q-TOF-MS technology has been applied to the analysis of non-volatile migrants from new active packaging materials. The materials tested were based on polypropylene (PP), ethylene-vinyl alcohol copolymer (EVOH), and poly(ethylene terephthalate) (PET). The active packaging materials studied were one PP film containing a natural antioxidant, and two PP/EVOH films, two PET/EVOH films and one coextruded PP/EVOH/PP film containing natural antimicrobials. The chemical structure of several compounds was unequivocally identified. The analysis revealed the migration of some of the active substances used in the manufacture of active packaging, such as caffeine (0.07?±?0.01?μg/g), carvacrol (0.31?±?0.03?μg/g) and citral (0.20?±?0.01?μg/g). Unintentionally added substances were also found, such as citral reaction compounds, or citral impurities present in the raw materials.     

Screening and characterizing the quality markers of Selaginella tamariscina (P. Beauv.) Spring using metabonomics and molecular networking

Quality control of traditional Chinese medicine (TCM) should be linked with the authentication and efficacy of TCM. Selaginella tamariscina is a frequently used traditional Chinese herbal medicine. However, its quality control is still difficult due to its multiple adulterants. We established quality markers (Q-markers) of S. tamariscina by using metabolomics, molecular networking and network pharmacology to improve the authenticity study and quality control of S. tamariscina. In this study, ultra high performance liquid chromatography-mass spectrum (UHPLC-MS) coupled with multivariate statistical analyses was applied to distinguish between S. tamariscina samples and their confusing adulterants. Principal component analysis, hierarchical clustering analysis (PCA), hierarchical clustering analysis (HCA) and partial least squares discriminant analysis (PLS-DA) were employed to screen the distinguishing markers from S. tamariscina samples and their adulterants. The top-2 distinguishing markers were isolated from S. tamariscina and identified by molecular networking together with nuclear magnetic resonance spectroscopy (NMR). Network pharmacology predicted the bioactivity and cytotoxicity of the top-2 distinguishing markers. The top-2 distinguishing markers were adopted as Q-markers of S. tamariscina for content determination. Based on the results of ultra performance liquid chromatography-quardrupole-time of flight mass spectrometry (UHPLC-QTOF-MS) metabolomics, we revealed that selaginellins could only be detected in S. tamariscina samples and contributed greatly to discriminating S. tamariscina samples from their confused species. The top-2 distinguishing markers were isolated and purified from S. tamariscina extract. Then, they were further identified as selaginellin and selaginellin A by molecular networking and NMR. Network pharmacology predicted the antitumor activity of selaginellin and selaginellin A, while the cytotoxicity assay verified their bioactivity. In conclusion, selaginellin and selaginellin A were selected as Q-markers for the determination and quality evaluation of S. tamariscina based on ultra performance liquid chromatography-triple quadrupole tandem mass spectrometry (UHPLC-QQQ-MS). The ranges of the concentrations of selaginellin and selaginellin A were 41.57–44.89 μg/g and 15.09–16.75 μg/g, respectively. This study provides a novel strategy combining Ultra performance liquid chromatography mass spectrometry based (UHPLC-MS-based) metabolomics with molecular networking for rapid species identification of S. tamariscina and discovery of the Q-markers of TCM.     

Isolation and structure elucidation of a new prenylcoumarin from Murraya paniculata var. omphalocarpa (Rutaceae)

A new C-8 prenylated 5,7-dimethoxycoumarin named omphamurrayin was isolated from the leaves of Murraya paniculata var. omphalocarpa, and its structure was established as 5,7-dimethoxy-8-(1-oxo-2-senecioyl-3-methyl-3-butenyl)-2H-1-benzopyran-2-one on the basis of the spectroscopic evidence. The taxonomic status of M. paniculata var. omphalocarpa is briefly discussed, along with its synonymity to M. paniculata from the chemosystematic viewpoint.     

Chemical composition of essential oil and in vitro antioxidant activities of the essential oil and methanol extracts of Eucalyptus loxophleba

This study was designed to examine the chemical composition of the essential oil and the antioxidant activity of the essential oil and methanol extracts of Eucalyptus loxophleba Benth. subsp. The chemical composition of the essential oil of the leaves of E. loxophleba was analysed by GC and GC/MS. The main constituents of the oil were found to be 1,8-cineole (39.4%), methyl amyl acetate (19.8%) and aromadendrene (10%). Antioxidant activities of the samples were determined by two different test systems namely DPPH and β-carotene/linoleic acid. In the DPPH system, the highest radical-scavenging activity was shown by the polar subfraction of the methanol extract (15.2?±?1.7?μg?mL?1). Also, in the second case, the inhibition capacity (%) of the polar subfraction (94.1?±?1.3) was found to be stronger. In addition, the amounts of total phenol components in the polar subfraction (273.0?±?2.6?μg?mg?1) and nonpolar subfraction (146.3?±?2.5?μg?mg?1) were determined.     

HPLC-DAD结合交替三线性分解二阶校正方法进行中药葛根中主要有效成分同时测定

应用高效液相色谱-二极管阵列联用仪(HPLC-DAD)结合基于交替三线性分解(ATLD)算法的二阶校正方法快速测定了中药葛根样中主要活性成分葛根素、大豆苷和大豆苷元的含量,实现了同时定量分析.色谱条件:甲醇-水(体积比为53∶47),检测波长范围为190～380nm,柱温为30℃,流速为1.0mL/min,进样量为20.0μL.预测的实际样中三种目标分析组分葛根素、大豆苷、大豆苷元的含量分别为(0.465±0.023),(0.553±0.015)和(0.098±0.005)mg/g,它们的加标回收率分别为(101.1±3.2)%,(100.4±6.4)%和(100.1±4.9)%.     

STUDIES ON THE PHOTOTOXICITY OF COUMARIN DERIVATIVES — I. PHOTOCYCLODIMERIZATION OF 5,7-DIMETHOXYCOUMARIN

Abstract— 5,7-DimethoxJtcoumarin (DMC) dimerizes through the C₄-photo-cycloaddition of 3,4-double bonds to form a syn head-to-tail dimer on direct irradiation ( Λ≥ 300 nm) in acetonitrile or benzene solution. The quantum yield of the photocyclodimerization in acetonitrile is 0.068 which is greater than that of coumarin.
In the presence of triplet sensitizers such as benzophenone, 5,7-dimethoxycoumarin forms an anti dimer with the quantum yield greater than 0.08. The structure of the photodimers has been elucidated by IR, UV, NMR, and mass spectrometry. The results of luminescence studies, triplet quenching and sensitization revealed that the syn head-to-tail dimer was formed via an excited singlet precursor, while the anti dimer was formed via the excited triplet state.     

PHOTOCYCLOADDITION REACTION OF 5,7-DIMETHOXYCOUMARIN TO THYMIDINE

Abstract— The photocycloaddition reaction of 5,7-dimethoxycoumarin to thymidine on direct irradiation (λ > 300 nm) is studied as a model for photosensitization reaction of furocoumarins. The major photoadducts were isolated by silica gel column and gel permeation chromatography. Each component of the photoadducts was further separated by reverse phase, paired-ion high performance liquid chromatography. The structure of these photoproducts isolated is consistent with 1:1 C₄-cycloadducts in accordance with characteristics of their UV, IR, NMR and mass spectra and elemental analysis data. The stereochemistry of each isomer was studied by Fourier transform NMR, UV and IR spectra. The fraction C has the anti head-to-tail configuration and the fraction D has the configuration of anti head-to-head. The fractions A and B probably have the syn configuration.