betadex and daidzin

The structure of the inclusion complexes of β-cyclodextrin (β-CD) with daidzein and daidzin in D2O were investigated using NMR spectroscopy. For the β-CD and daidzein system, two types of 1:1 complexes were formed with the daidzein deeply inserted into the CD cavity with different orientations. For the β-CD/daidzin system, a 1:1 complex was formed with the flavonoid part of daidzin entering the CD cavity from the wide rim. The inclusion complexes determined by NMR were constructed using molecular docking. Furthermore, the mixture of puerarin, daidzein and daidzin, which are the major isoflavonoid components present in Radix puerariae, was analyzed by diffusion-ordered spectroscopy (DOSY) alone and upon addition of β-CD in order to mimic chromatographic conditions and compare their binding affinities.

Topics: beta-Cyclodextrins; Isoflavones; Magnetic Resonance Spectroscopy; Molecular Docking Simulation; Molecular Structure

Acetic acid acts as one component of the mobile phase to influence separation of puerarin from daidzin when using β-cyclodextrin-substituted media. In this work considering an explicit acetic acid solution, host-guest complexes of β-cyclodextrin (β-CD) with puerarin and daidzin were investigated by molecular dynamics simulations. Computational results indicate different shuttle motions of puerarin and daidzin inside the cavity of β-CD. A model detailing the shuttle motion was constructed, and the relationships between shuttle depth and guest rotation angles, hydrogen bonds, and host-guest interaction energies were analyzed. The results can be used to explain the chromatographic retention mechanisms of puerarin and daidzin with β-CD, and to explore the complexity of host-guest interactions involving β-CD.

Topics: Acetic Acid; beta-Cyclodextrins; Chromatography; Isoflavones; Models, Molecular; Molecular Dynamics Simulation

In order to differentiate two species of Radix Puerariae (Radix Puerariae lobatae and Radix Puerariae thomsonii) and to determine major isoflavonoids (puerarin, daidzin, daidzein and genistein) in the samples, a simple high performance liquid chromatography (HPLC) method with isocratic elution employing cyclodextrins (CDs) as mobile phase additives was developed. Various factors affecting the retention of isoflavonoids in the C(18) reversed-phase column, such as the nature of CDs, the concentration of hydroxypropyl-β-cyclodextrin (HP-β-CD) and the methanol percentage in the mobile phase, were studied. Experimental results confirmed that HP-β-CD, as a very effective mobile phase additive, could markedly reduce the retention of isoflavonoids, especially daidzein and genistein. The elution of four isoflavonoids could be achieved on a Kromasil(®) C(18) column within 56 min by using the methanol-water contained 5 mM HP-β-CD (25/75, v/v) mixture as the mobile phase. The formation of the inclusion complexes between isoflavonoids and HP-β-CD explained the modification of the retention of analytes. The apparent formation constants determined by HPLC confirmed that the stoichiometry of HP-β-CD-isoflavonoid complexes was 1:1, and the stability of the complexes depended on the size and property of isoflavonoids. The optimized method was successfully applied for the simultaneous determination of major isoflavonoids in P. lobatae and P. thomsonii samples. This work provides a useful method for the analysis of traditional Chinese herbs.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; beta-Cyclodextrins; Chromatography, High Pressure Liquid; Drugs, Chinese Herbal; Genistein; Isoflavones; Pueraria

Beta-cyclodextrin (β-CD) is an ideal candidate for a host molecule, and it is used as such in drug delivery and separation technology. The structural behavior of free β-CD and host-guest complexes of β-CD with two isoflavonoid isomers (puerarin and daidzin) in aqueous alcohol solutions, covering methanol, ethanol, 2-propanol, and 1-propanol, was investigated through molecular dynamics (MD) simulations. The MD results highlighted aspects of the structural flexibility and rigidity of β-CD in different alcohol solutions. The alcohol residence time within the β-CD cavity, solvent distribution around β-CD, and guest-induced structural changes were analyzed. Interaction with puerarin endowed β-CD with a more rigid structure than with daidzin and a weaker ternary complex β-CD/puerarin/alcohol was formed with a local participation of water molecules. The retention behavior of puerarin and daidzin on a β-CD-coupled medium was determined via chromatographic experiments and simulation results provided a structural explanation for such interactions.

Topics: Alcohols; beta-Cyclodextrins; Hydrogen Bonding; Isoflavones; Isomerism; Molecular Dynamics Simulation; Solvents

A novel method using column chromatography on oligo-β-cyclodextrin-Sepharose HP for the preparation of high purity daidzin from crude soybean samples was proposed in this work. The isoflavone of daidzin in sample A and B was purified under the optimum mobile phase composed of methanol/acetic acid/water=20.0/8.0/72.0 (v/v/v) at a flow-rate of 1.0 mL/min in one-step operation with a purity of 97.2% and 98.1%, a recovery of 95.3% and 96.3% respectively. The target products in isolated fraction were detected and characterized by HPLC analysis and ESI-MS spectrum. Preparative separation with sample-load of up to 2.42 mg/mL medium gave satisfactory results for daidzin with the purities over 97% and recoveries approximately 90%. Molecular docking simulations were utilized to help demonstrate the inclusion complexation between β-cyclodextrin and the isoflavones in samples through inclusion geometries and calculations of the binding energies. The prediction of the elution orders with AUTODOCK and SURFLEX-DOCK were validated by the chromatographic results.

Topics: beta-Cyclodextrins; Chromatography, High Pressure Liquid; Glycine max; Isoflavones; Models, Statistical; Molecular Dynamics Simulation; Plant Extracts; Sepharose; Spectrometry, Mass, Electrospray Ionization

Puerarin and daidzin, two major isoflavonoids of Radix puerariae , are widely adopted in traditional Chinese medicine. Foundational aspects related to separating the two compounds are essential to develop a more economical purification process. Inclusion models of the two compounds with beta-cyclodextrin (beta-CD) have been investigated by molecular dynamics simulation. Computational results reveal that both puerarin and daidzin can induce a conformational change of beta-CD, which is compressed in one direction and stretched in the other. The effect of solvent and media on the conformational change of beta-CD and the movement of guest molecules inside the cavity has been investigated. Furthermore, hydrogen bonding interactions have been analyzed, and the results have been utilized for the explanation of separating puerarin from daidzin.

Topics: beta-Cyclodextrins; Carcinogens; Enzyme Inhibitors; Hydrogen Bonding; Isoflavones; Models, Chemical; Models, Molecular; Molecular Dynamics Simulation; Molecular Structure; Vasodilator Agents