Nonaqueous capillary electrophoresis coupled with laser-induced native fluorescence detection for the analysis of berberine, palmatine, and jatrorrhizine in Chinese herbal medicines

LIF detection is one of the most sensitive detection methods for CE. However, its application is limited because the analyte is usually required to be derivatized with a fluorescent label. As a result, LIF is seldom used to analyze active ingredients in plants. In this work, we introduce a rapid, simple, and sensitive method of nonaqueous CE (NACE) coupled with laser-induced native fluorescence detection for the simultaneous analysis of berberine, palmatine, and jatrorrhizine. This method skillfully utilizes the native fluorescence of these alkaloids and requires no troublesome fluorescent derivatization. As these alkaloids can fluoresce to some degree, they were simply detected by a commercially available 488 nm Ar+ laser. The native fluorescence of the analytes was greatly enhanced by nonaqueous media. Compared with the reported UV detection method, much lower LOD was achieved (6.0 ng/mL for berberine, 7.5 ng/mL for palmatine, and 380 ng/mL for jatrorrhizine). This method was successfully applied to analyze berberine, palmatine, and jatrorrhizine in two Chinese herbal medicines, Rhizoma coptidis and Caulis mahoniae.     

Determination of berberine by measuring the enhanced total internal reflected fluorescence at water/tetrachloromethane interface in the presence of sodium dodecyl benzene sulfonate

A highly sensitive method for determination of berberine is proposed based on the measurements of total internal reflected fluorescence (TIRF) at water/ tetrachloromethane (H₂O/CCl₄) interface. In the pH range of 2.6–5.7, the co-adsorption of the berberine with the anionic surfactants such as sodium dodecyl benzene sulfonate (SDBS), sodium dodecylsulfonate (SDS), and sodium lauryl sulfate (SLS) occurs at the H₂O/CCl₄ interface, resulting in greatly enhanced TIRF signal characterized by the emission at 526 nm when excited with a 351 nm light beam. The enhanced TIRF intensity is in proportion to the berberine concentration in the range 0.2–10.0×10^-7 mol L^-1. The limit of detection is 1.7×10^-9 mol L^-1 (3). It was found that ions such as Ca(II), Cu(II), Fe(III), Cd(II), Mg(II), Zn(II), Pb(II), and Al(III) can be allowed larger than 1.0×10^-4 mol L^-1. Meanwhile, the organic compounds such as vitamin B, saccharine, and amino acid do not display any effect for the present TIRF method even if they are larger than 1.0×10^-2 mol L^-1in high concentration levels (larger than 1.0×10^-5 mol L^-1). The results of determination for synthetic samples were agreement with the desired values, and the ones for tablets were identical with those obtained according to the method of Chinese Pharmacopoeia.     

Preliminary studies of berberine and its semi-synthetic derivatives as a promising class of multi-target anti-parkinson agents

Parkinson’s disease (PD) is a neurodegenerative disorder bearing motor and nonmotor symptoms. The treatment today is symptomatical rather than preventive or curative and this leaves the field open for the search of both novel molecular targets and drug candidates. Interference with α-synuclein fibrillation, monoamine oxidase (MAO) inhibition, modulation of adenosine receptors and the inhibition of specific phosphodiesterase (PDE) isoforms are some of the currently pursued strategies. We synthesised and studied some semi-synthetic berberine derivatives using a set of in silico tools. We evaluated their drug-likeness and tested the compounds against a set of target proteins involved in the onset or progression of PD, with a particular attention to MAO-B. Preliminary in vitro assay on MAO-B confirmed our in silico predictions.     

盐酸小蘖碱与氧氟沙星相互作用的研究

利用荧光光谱及紫外光谱法研究发现pH 7.4的Tris-HCl缓冲溶液中盐酸小蘖碱(BC)与氧氟沙星(OFLX)形成配合物, 导致氧氟沙星溶液荧光猝灭, 猝灭类型主要为静态猝灭. 测定了该反应的表观结合常数、结合位点数及结合热力学参数, 上述作用过程是一个熵增加、自由能降低的自发分子间作用过程, BC与OFLX之间以静电和疏水作用力为主;根据Frster能量转移理论, 测得供体与受体间结合距离r和能量转移效率E.     

Structural study of 8-azole derivatives of protoberberine alkaloids: experimental and quantum chemical approach

New derivatives of protoberberine alkaloids were prepared by nucleophilic addition of some azoles (differing in bulkiness) to the iminium functionality of the quaternary protoberberine alkaloids. Compounds were structurally characterized mainly by ¹H and ¹³C NMR spectroscopy, and the structure of 8-carbazol-1-yl-7,8-dihydroberberine was determined using single-crystal X-ray diffraction. Additionally, conformational behaviors of five derivatives varying in bulkiness of the azole moiety have been investigated by low temperature NMR spectroscopy and quantum chemical calculations. Ring current effects of pyrrole and carbazole moieties on selected ¹H NMR resonances have been characterized, visualized, and discussed.     

小檗碱在TLC原位的FT-SERS研究

应用表面增强技术将薄层色谱与近红外傅里叶变换拉曼光谱联用，获得了中成药三黄片中主要有效成分小檗碱在薄层原位的傅里叶变换表面增强拉曼光谱（FT－SERS）。研究表明，在薄层原位约2.5μm样品的FT－SERS与纯固体样品的FT－Raman光谱的主要特征峰波数基本一致，相对强度有一定变化，出现特别增强的拉曼峰是波数为727nm的芳香环上CH键面内变形振动峰。小檗碱分子以异喹啉环共轭体系的π电子与表面增强活性物质银晶体微粒相互作用，呈平面吸附样式。获得了中成药三黄片中主要有效成分小檗碱分离与高灵敏度指纹检测的可靠的新方法。     

小檗碱质谱碎片离子稳定性分析及碎裂机理的量子化学研究

用量子化学B3LYP/6-31G(d)方法, 研究了小檗碱质谱碎片离子的稳定性规律. 通过几何参数分析、 结合能计算和前线分子轨道分析, 研究碎片离子可能的活性部位及各部位相对反应活性, 并从理论上探讨了质谱碎裂机理. 结合能计算结果表明, 分子离子中C9所连甲氧基的C—O键比C10所连甲氧基的C—O键更容易断裂. 同时发现, 质谱碎裂过程中, 氢的解离促进了羰基的解离, 即质谱中常见的解离CO的过程.     

Fundamental characteristics of synthetic adsorbents intended for industrial chromatographic separations

With the aim of obtaining comprehensive information on the selection of synthetic adsorbents for industrial applications, effect of pore and chemical structure of industrial-grade synthetic adsorbents on adsorption capacity of several pharmaceutical compounds was investigated. For relatively low molecular mass compounds, such as cephalexin, berberine chloride and tetracycline hydrochloride, surface area per unit volume of polystyrenic adsorbents dominated the equilibrium adsorption capacity. On the contrary, effect of pore size of the polystyrenic adsorbents on the equilibrium adsorption capacity was observed for relatively high molecular mass compounds, such as rifampicin, Vitamin B12 and insulin. Polystyrenic adsorbent with high surface area and small pore size showed small adsorption capacity for relatively high molecular mass compounds, whereas polystyrenic adsorbent with relatively small surface area but with large pore size showed large adsorption capacity. Effect of chemical structure on the equilibrium adsorption capacity of several pharmaceutical compounds was also studied among polystyrenic, modified polystyrenic and polymethacrylic adsorbents. The modified polystyrenic adsorbent showed larger adsorption capacity for all compounds tested in this study due to enhanced hydrophobicity. The polymethacrylic adsorbent possessed high adsorption capacity for rifampicin and insulin, but it showed lower adsorption capacity for the other compounds studied. This result may be attributed to hydrogen bonding playing major role for the adsorption of compounds on polymethacrylic adsorbent. Furthermore, column adsorption experiments were operated to estimate the effect of pore characteristics of the polystyrenic adsorbents on dynamic adsorption behavior, and it is found that both surface area and pore size of the polystyrenic adsorbents significantly affect the dynamic adsorption capacity as well as flow rate.     

The drug interaction potential of berberine hydrochloride when co-administered with simvastatin,fenofibrate, gemfibrozil,metformin, glimepiride,nateglinide, pioglitazone and sitagliptin in beagles

Berberine (BBR) hydrochloride is a traditional Chinese medicine with unique hypoglycemic and lipid-lowering effects discovered in recent years. The combination of BBR with other hypoglycemic drugs and lipid-lowering drugs could become a promising treatment strategy. With the aim of evaluating the potential drug-drug interaction (DDI) based on the pharmacokinetics between BBR and simvastatin, fenofibrate, gemfibrozil, metformin, glimepiride, nateglinide, pioglitazone and sitagliptin in beagles, an UPLC-MS/MS method has been developed and validated. The analytes and internal standards were extracted from plasma samples using a magnetic solid phase extraction technique, and then separated by a Luna® Omega C₁₈ column (20.0 × 2.0 mm, 1.6 μm) with water containing 3 mM ammonium and 0.1% formic acid and acetonitrile containing 3 mM ammonium and 0.1% formic acid as the mobile phase. Validation of the UPLC-MS/MS method was carried out following the criteria of the Chinese Pharmacopeia, mainly including specificity, carryover, calibration curve, crosstalk, precision, accuracy, dilution integrity, matrix effect, recovery and stability. The results showed that all the criteria of the method validation met the Chinese Pharmacopoeia guidelines, and the proposed UPLC-MS/MS method was proven to be sensitive, simple and specific to determine all the analytes in the beagles’ plasma samples simultaneously. Meanwhile, the potential DDI between BBR and simvastatin, fenofibrate, gemfibrozil, metformin, glimepiride, nateglinide, pioglitazone and sitagliptin was confirmed in this paper, especially for simvastatin, fenofibrate, gemfibrozil and glimepiride.     

小檗碱的药物代谢动力学

小檗碱是中药三棵针的主要有效成分之一，为了研究小檗碱的药物代谢动力学，本文采用胶束增敏荧光法对小檗碱在兔体内的血药浓度进行２４ｈ监测，求出毓药物代谢动力学参数，结果表明小檗碱在动物体内的Ｋａ为１．６３７ｈ＾－１，ｔ１／２（α） ０．３８６９ｈ，ｔ１／２（β）为６．７６ｈ，Ｋ２１为０．１５５３ｈ＾－１，Ｋ１２ｏ ０．０３８４ｈ＾－１，ＡＵＣ为２１１。９４μｇ．ｈ／ｍｌ。