Application of experimental design and radial basis function neural network to the separation and determination of active components in traditional Chinese medicines by capillary electrophoresis

Orthogonal design has been used to the optimization of separation and determination of two active components in traditional Chinese medicines by capillary electrophoresis. The concentration of phosphate, applied voltage, organic modifier content and buffer pH were selected as variable parameters. Their different effects on peak resolution were studied by the experimental design method. Optimized separation conditions were obtained and successfully applied to the separation and determination of aconitine and hypaconitine in Aconitum medicinal herbs. Good separation was achieved within 7 min using a buffer system composed of 20 mmol L⁻¹ phosphate and 35% acetonitrile at pH 9.5. The applied voltage was 14 kV and the detection was set at 235 nm. In addition, a radial basis function neural network with a “4-18-1” structure was developed based on the experimental results of orthogonal design and uniform design, and was applied to the prediction of peak resolution of the two active components under the optimum separation conditions given by orthogonal design. The predicted results were in good agreement with the experimental values, indicating that radial basis function neural network is a potential way for the selection of separation conditions in capillary electrophoresis.     

Separation and determination of aconitine alkaloids in traditional Chinese herbs by nonaqueous capillary electrophoresis

An easy, rapid, and simple nonaqueous capillary electrophoresis (NACE) method was developed for the identification and determination of three aconitine alkaloids, hypaconitine (HN), aconitine (AN), and mesaconitine (MN) within 6 min. The most suitable running buffer was composed of 60 mM ammonium acetate, 0.5% acetic acid, and 15% acetonitrile (ACN) in methanol with a fused-silica capillary column (50 cm x 75 microm ID). In the concentration range 12.5-1000 mg/L the calibration curves reveal linear relationships between the peak area for each analyte and its concentration (correlation coefficients: 0.9997 for HN, 0.9999 for AN, and 0.9995 for MN). The relative standard deviations of the migration time and peak area of the three alkaloids were 0.13, 0.57, 0.33 and 2.87, 1.06, 3.49%, respectively. The method was successfully applied to determine the three alkaloids in two commonly used traditional Chinese herbal medicines, the recoveries of the three constituents ranging between 94.7-101.9% for HN, 98.3-102.3% for AN, and 98.1-104.6% for MN.     

Rapid construction of the unique BCD ring system of tricyclo[6.2.1.0] undecane in the C19-diterpenoid alkaloid aconitine

A model study leading to the preparation of the unique tricyclo [6.2.1.0] undecane BCD ring systems of aconitine is described. The synthesis features an unprecedented diastereoselective oxidative dearomatization/dimerization/retro-DA/IMDA cascade reaction and a highly efficient Wagner-Meerwein rearrangement.     

HPLC-MS测定桂附地黄丸中三种双酯型生物碱含量

目的:建立测定桂附地黄丸中新乌头碱、乌头碱和次乌头碱的高效液相色谱-质谱分析方法(HPLC-MS)。方法:采用HPLC-MS,色谱柱为Polaris C18-A(50 mm×2.0 mm,5μm),流动相为甲醇-水(90 10),流速为0.2(mL.m in-1),质谱检测采用电喷雾电离源正离子检测。结果:新乌头碱、乌头碱和次乌头碱浓度分别在46.4～278.4(ng.mL-1)(r=0.999 5)、6.8～108.8(ng.mL-1)(r=0.999 8)和48.2～771.2(ng.mL-1)(r=0.999 7)范围内线性关系良好,平均回收率(n=6)分别为97.9%(RSD=3.0%)、98.2%(RSD=3.2%)和97.6%(RSD=3.0%)。结论:该法是一种快速、灵敏、准确的分析方法,可为桂附地黄丸的质量控制提供科学依据。     

紫外光谱与ITC法研究乌头碱与粘虫DNA相互作用

DNA是生物体遗传信息的载体,研究药物与DNA的相互作用对探讨其作用机理及新药的设计合成具有重要意义。利用紫外吸收光谱技术,微量量热法,等温滴定量热法以及分子模拟技术研究了乌头碱在水溶液中的溶解行为,探讨了乌头碱与粘虫DNA、鲑鱼精DNA、小牛胸腺DNA的相互作用。实验发现,乌头碱在水溶液中的溶解过程为准一级反应,半衰期(t_1/2)为0.691 h。乌头碱分别与三种DNA作用均为体现出沟槽和表面两种结合形式：沟槽结合时,结合常数Ka₁为105,结合位点数为0.40~0.60,且反应为焓驱动的自发过程;表面结合时,乌头碱分子仅与DNA表面发生作用而并未嵌到DNA分子的疏水部分,结合常数Ka₂为103,结合位点较大。分子模拟显示,乌头碱均以氢键作用力结合在三种DNA分子的沟槽区,且乌头碱分子中C₈上的酯基对粘虫DNA,鲑鱼精DNA和小牛胸腺DNA链上的碱基有特异性识别,依次为T33,T34和G16,C9,C8。模拟计算获得反应的结合能与实验测定所得ΔG值接近,同时,依据实验数据判定的作用力类型在分子模拟中得到印证,即理论计算与实验基本吻合。     

人参茎叶皂苷对实验性小鼠心电改变及死亡时间的影响

目的研究人参茎叶皂苷对实验性心律失常的作用。方法在氯仿和乌头碱诱发的两种小鼠心律失常模型上,分别观察人参茎叶皂苷的抗心律失常作用。结果人参茎叶皂苷对氯仿诱发的小鼠心律失常具有抗心律失常作用,对乌头碱诱发的小鼠心律失常有预防作用,并呈剂量依赖关系。结论人参茎叶皂苷对两种方法诱发的心律失常都具有对抗作用。     

复方中药四逆汤中乌头碱类二萜生物碱的电喷雾串联质谱研究

利用电喷雾串联质谱方法不经柱分离而直接分析复方中药四逆汤中二萜生物碱的组成,乌头碱类二萜生物碱在质谱条件下形成质子化分子,一种生物碱对应一个分子离子峰.检测到了苯甲酰单酯型、双酯型和脂类生物碱等18种二萜生物碱,其中苯甲酰中乌头原碱等单酯型生物碱是四逆汤中的主要生物碱成分.     

薄层色谱法限量检查伤湿祛痛膏中的乌头碱

以V(正己烷):V(乙酸乙酯):V(无水乙醇)=6.4:3.6:1为展开剂,稀碘化铋钾试液为显色剂,建立了伤湿祛痛膏中乌头碱的薄层色谱限量检查方法.该方法可用于伤湿祛痛膏的质量控制.     

A New Method for Preparation and Characterization of Lipo-alkaloid

IntroductionAconitine typealkaloids (1)andtheirderiva tives ,lipo alkaloids(2 ) ,aresecondarymetabolitesintherootsofaconite[1] .Thesecompoundsareattract ingmoreattentionduetotheirpotentialbiologicalac tivity[2 ] .Althoughaconitine typealkaloidscanbeiso latedbythechromatographicmethod ,itisadifficulttasktoacquirepurelipo alkaloidsfromplantsbecauseoftheirextremesimilarityinstructure[3] .Awidelyusedsynthesismethodfortheprepara tionoflipo alkaloidshasbeenfirstreportedbyPelleti eretal .[4 ] ,bywhi…