Assay of free ferulic acid and total ferulic acid for quality assessment of Angelica sinensis

Activity of Chinese Danggui (DG), the processed root of Angelica sinensis (Oliv.) Diels, is linked to the ferulic acid content but the stability of ferulic acid during extraction for medicinal use is not known. The stabilities of ferulic acid and coniferyl ferulate were evaluated in the extracts of DG using a variety of extraction solvents. These included various combinations and proportions of methanol, water, formic acid, 1 M aqueous hydrochloric acid and 2% sodium hydrogen carbonate (NaHCO3) in water. Coniferyl ferulate was found liable to hydrolyze into ferulic acid in neutral, strongly acidic and basic solvents, where heat and water could facilitate this hydrolysis. However, the hydrolysis was relatively resisted in weakly organic acid. Based on the stability evaluation, two new terms, namely: free ferulic acid and total ferulic acid, were suggested and defined. Free ferulic acid refers to the natural content of ferulic acid in herbs. Total ferulic acid means the sum of free ferulic acid plus the amount of related hydrolyzed components. Meanwhile, the high-performance liquid chromatographic (HPLC) method was developed to assay free ferulic acid and total ferulic acid in DG using methanol-formic acid (95:5) and methanol-2% NaHCO3 in water (95:5) as extraction solvents, respectively. Ten DG samples were investigated on their contents of free and total ferulic acid. The results indicated that the amount variety of free ferulic acid was larger than that of their counterparts, and the ratio of total ferulic acid to free ferulic acid was 4.07 +/- 2.73 (mean +/- SD, n = 10). The chemical assay of DG using total ferulic acid content would be a better choice to assess the herbal quality and was recommended.     

Quantitative determination of sodium stearyl fumarate in a tablet formulation from continuous manufacturing using a high-pH reversed-phase HPLC method

This study demonstrates the first use of a reversed-phase (RP) high-performance liquid chromatography method with a high-pH buffer for the analysis of sodium stearyl fumarate (SSF) from a tablet formulation. After examining the retention time and peak shape using various buffer concentrations, buffer pH, and RP stationary phases, an optimized method was established using the XBridge® BEH C18 at high pH. This column was further evaluated for method specificity, accuracy, precision, linearity, stability, and sensitivity. Finally, the method was successfully used as a convenient and robust analytical procedure to accurately quantitate SSF in stratified tablets from a continuous manufacturing process to confirm the excipient uniformity throughout the process.     

流动注射化学发光抑制法测定阿魏酸钠

提出了Fe2+-H2O2-亚甲基蓝化学发光新体系并用于阿魏酸钠的测定。实验发现,在酸性介质中,Fe2+-H2O2体系可与亚甲基蓝反应产生极强的化学发光,阿魏酸钠对此化学发光具有显著的抑制作用。据此,结合流动注射技术,建立了阿魏酸钠化学发光分析新方法。研究了影响化学发光强度的因素,化学发光信号的降低值(ΔI)与阿魏酸钠浓度在4.5×10-6～4.5×10-5mol/L范围内呈良好的线性关系,方法的检出限为7.0×10-7mol/L。对4.8×10-6mol/L的阿魏酸钠进行了11次平行测定,其RSD=0.8%,该法已用于片剂中阿魏酸钠含量的测定。     

微波协同阳离子交换树脂催化合成阿魏酸乙酯

以732型强酸性阳离子交换树脂为催化剂,在微波辐射下用阿魏酸与乙醇酯化合成了阿魏酸乙酯.通过单因素实验,考察了催化剂活化方法对催化剂活性的影响,结果表明,微波法活化阳离子交换树脂的催化性能好.通过单因素实验和正交实验,考察了催化剂用量、醇酸摩尔比、微波辐射时间、微波辐射功率等因素对反应的影响.确定了最佳反应工艺条件:阿魏酸0.1mol,酸醇摩尔比5:1,催化剂用量为反应物质量的35%,微波功率300w,反应时间30min,产率达84.2%.732型树脂催化剂可再生循环使用,重复使用4次,产率不低于80%.     

Screening and analysis of an antineoplastic compound in Rhizoma Chuanxiong by means of in vitro metabolism and HPLC-MS

A new screening and analysis method that combines in vitro metabolism with high-performance liquid chromatography-mass spectrometry (HPLC-MS) was developed for the screening and analysis of an antineoplastic compound, coniferyl ferulate, which is present in the rhizome of Rhizoma Chuanxiong. Infrared (IR), ultraviolet visible spectroscopy (UV-Vis), nuclear magnetic resonance (NMR) and element analysis were used to identify the molecular structure of coniferyl ferulate. The quantitative analysis of coniferyl ferulate in different extracts of Rhizoma Chuanxiong was carried out, and the metabolism of coniferyl ferulate was investigated by in vitro incubation with rat liver homogenate. The metabolite of coniferyl ferulate, ferulic acid ethyl ester, was identified by HPLC-MS, UV-Vis and IR. In addition, antineoplastic activities of coniferyl ferulate and ferulic acid ethyl ester were detected by the MTT assay. The observed inhibition rate of coniferyl ferulate on the activity of HeLa cells was over 80% at 5.4 ng μl⁻¹. However, its metabolite, ferulic acid ethyl ester, showed no antineoplastic activity in vitro.      

Applications of polymethacrylate-based monoliths in high-performance liquid chromatography

Monolithic columns were introduced in the early 1990s and have become increasingly popular as efficient stationary phases for most of the important chromatographic separation modes. Monoliths are functionally distinct from porous particle-based media in their reliance on convective mass transport. This makes resolution and capacity independent of flow rate. Monoliths also lack a void volume. This eliminates eddy dispersion and permits high-resolution separations with extremely short flow paths. The analytical value of these features is the subject of recent reviews. Nowadays, among other types of rigid macroporous monoliths, the polymethacrylate-based materials are the largest and most examined class of these sorbents. In this review, the applications of polymethacrylate-based monolithic columns are summarized for the separation, purification and analysis of low and high molecular mass compounds in the different HPLC formats, including micro- and large-scale HPLC modes.     

中孔分子筛MSU及其杂原子衍生物的合成、表征和催化性能研究

以十八烷基聚氧乙烯基醚为模板剂,在ＳiＯ２的等电点（ＰＨ值为２）下,成功地合成了 具有ＭＳＵ结构的中孔ＳiＯ２分子筛及其Ｔｉ、Ｚｒ和Ｖ取代衍生物。用ＸＲＤ、Ｘ２吸 附／脱附、ＤＲＵＶ－Ｖｉｓ和元素分析等手段,对它们的孔道及骨架结构进行了全面表征。催化性能评价结果表明,在乙酸介质中,Ｔｉ、Ｚｒ和Ｖ等过渡金属原子取代的分子筛样品可以催化苯乙烯氧化为苯甲醛的反应,且活笥和选择性较高。     

Biphenyl Ferulate from Glehnia littoralis

From the underground parts of Glehnia littoralis Fr.Schmidt ex Miquel (Umbelliferae), a new compound named glehnilate was obtained. Its structure was determined by analysis of its spectral data.     

Synthesis of amphiphilic cationic copolymers poly[2‐(methacryloyloxy)ethyl trimethylammonium chloride‐co‐stearyl methacrylate] and their self‐assembly behavior in water and water‐ethanol mixtures

A series of amphiphilic cationic random copolymers, namely poly[2‐(methacryloyloxy)ethyl trimethylammonium chloride‐co‐stearyl methacrylate] or poly(MADQUAT‐co‐SMA), have been synthesized via conventional free‐radical copolymerization using 2,2′‐azobisisobutyronitrile (AIBN) as initiator and n‐dodecanethiol as chain transfer agent. The resultant products were then characterized by FT‐IR, ¹H NMR, MALDI‐TOF MS measurements. From the number‐average molecular weights of the copolymers, we can conclude that these copolymers have oligomeric structure with a limited number of hydrophilic and hydrophobic moieties in a short polymer chain. The reactivity ratios (r_MADQUAT = 0.83, r_SMA = 0.25) between the hydrophilic MADQUAT monomer and the hydrophobic SMA monomer were calculated by the Finemann and Ross method, which was based on the results of ¹H NMR analysis. The surface activity of the random copolymers was studied by the combination of surface tension and contact angle measurement, and the results indicated that these copolymers possess relatively high surface activity. The critical aggregation concentrations (cac) of the copolymers in aqueous solution were determined by fluorescence probe method as well as surface tension measurement. The different nanoparticles of poly(MADQUAT‐co‐SMA) copolymers formed in pure water or ethanol‐water mixture were proved by the particle size and size distribution in the measurement of dynamic light scattering (DLS). Furthermore, using transmission electron microscopy (TEM), we could observe various self‐assembly morphologies of these random copolymer. All these results show that the amphiphilic cationic random copolymers have a good self‐assembly behavior, even if they are ill‐defined copolymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4670–4684, 2009     

1,3-二环基碳化二亚胺催化的阿魏酸对硝基苯酚酯一步合成法

1;3-二环基碳化二亚胺催化的阿魏酸对硝基苯酚酯一步合成法;酯化反应