Coupling oligo-β-cyclodextrin on polyacrylate beads media for separation of puerarin

Preparative separation and purification of epigallocatechin gallate from green tea extracts using a silica adsorbent containing β-cyclodextrin

A silica adsorbent containing β-cyclodextrin (β-CD) has been developed and used for the separation and purification of epigallocatechin gallate (EGCG) from the green tea extracts. The batch adsorption experiments demonstrated that, the β-CD bonded silica adsorbent possessed excellent adsorption equilibrium capacity (> 55 mg/g adsorbent) and adsorption ratio (>95%) for EGCG compared to the other tea catechins and caffeine. The excellent adsorption capacity and selectivity for EGCG are attributed to the specific interactions between β-CD and EGCG. The preparative separation and purification performance of EGCG on the β-CD bonded silica column (220 mm L × 15 mm i.d., 40-63 μm) was then evaluated. The column was operated in the polar organic mode using methanol/acetonitrile/acetic acid as the mobile phase and eluted under a three-step gradient elution program. The sample was dissolved in acetonitrile and loaded on a preparative scale of about 0.8 mg/g adsorbent. Under the optimal chromatographic conditions, the target compound, EGCG, being the most retained species, was obtained at a purity of about 90% with a recovery of about 90%. The productivity of EGCG was about 6 mg per injection, which can be further increased by scaling-up the chromatographic system.

NMR studies on puerarin and its interaction with beta-cyclodextrin

The interaction between puerarin and β-cyclodextrin (CD) has been studied in D(2)O, H(2)O/acetone-d(6), acetone-d(6) and DMSO-d(6) solutions by (1)H NMR spectroscopy. The NMR data obtained from hydroxy protons indicate that the formation of the inclusion complex between the two molecules is not stabilized by strong hydrogen bond interactions. The sugar part of puerarin as well as the A ring are outside the β-CD cavity while the B and C rings are located inside the cavity and the interaction is mainly stabilized by hydrophobic interactions. In DMSO at 30°C and in acetone-d(6)/H(2)O at temperature below -5°C, doubling of some signals indicated that, in these solvent systems, free rotation of the C-glycosyl bond was restricted due to the steric hindrance between the phenolic hydroxy group at C-7 and the bulky sugar moiety at C-8. In acetone, fast exchange of phenolic protons on the NMR timescale was observed, showing the effect of the solvent on the hindered rotation.

Characterization and selectivity studies of molecular imprinted membranes of Puerarin using scanning electron microscopy

Molecular-imprinted membranes of Puerarin were prepared by phase inversion technique with acrylonitrile-acrylic acid copolymer (P (AN-co-AA)). To characterize P (AN-co-AA), ubbelohde viscometer was used to measure its viscosity-molecular weight. P (AN-co-AA) with different molecular weight was used to prepare membranes. The copolymer-dimethyl sulfoxide solution with Puerarin (PU) template was coagulated in water at various temperatures. The increase in P (AN-co-AA) molecular weight and the decrease in coagulation temperature caused an increase in PU recognition property of the resultant membrane. The PU imprinted membrane prepared with P (AN-co-AA) showed good selective ability to PU. The purity of PU increased from 56.51 to 98.41 wt%. Surface and cross-section morphology of the membranes were analyzed by using scanning electron micrograph. High-performance liquid chromatography was used for the quantification of Puerarin in isolated fraction.

Investigation of the inclusions of puerarin and daidzin with beta-cyclodextrin by molecular dynamics simulation

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.

Bioreactors and bioseparation

Along with the rapid development of life science, great attention has been increasingly given to the biotechnological products of cell cultivation technology. In the course of industrialization, bioreactor and bioproduct separation techniques are the two essential technical platforms. In this chapter, the current situation and development prospects of bioreactor techniques in China are systematically discussed, starting with the elucidation of bioreactor processes and the principle of process optimization. Separation technology for biological products is also briefly introduced.At present, a series of bioreactors made by Chinese enterprises have been widely used for laboratory microbial cultivation, process optimization studies, and large-scale production. In the course of bioprocess optimization studies, the complicated bioprocesses in a bioreactor could be resolved into different reaction processes on three scales, namely genetic, cellular, and bioreactor scales. The structural varieties and nonlinear features of various scales of bioprocess systems was discussed through considering the mutual effects of different scale events, namely material flux, energy flux, and information flux, and the optimization approach for bioprocesses was proposed by taking the analysis of metabolic flux and multiscale consideration as a core strategy.In order to realize such an optimization approach, a bioreactor system based on association analysis of multiscale parameters was elaborated, and process optimization of many biological products were materialized, which resulted in great improvement in production efficiency. In designing and manufacturing large-scale bioreactors, the principle of scaling up a process incorporated with flow field study and physiological features in a bioreactor was suggested according to the criterion for the scale-up of cellular physiological and metabolic traits. The flow field features of a bioreactor were investigated through computational fluid dynamics (CFD), and the design of a bioreactor configuration was carried out depending on multiscale studies of parameters correlation in a bioprocess. With respect to the development trend of bioreactor studies in China, the significance of the development of microbioreactors for high throughput strain screening and large-scale bioreactors for animal cell cultivation were put forward. Finally, the importance of studies of systems biology for bioprocesses based on bioinformation processing was raised, and the necessity of establishing a bioprocess information database and local area network (LAN) were emphasized as well.Bioseparation engineering plays a key role in biotechnology production. At present, many difficulties need to be resolved in the area. Scientists of China have made considerable progress in bioseparation engineering. This progress includes chromatography media, recycling aqueous two-phase systems (ATPS), affinity precipitation, molecular imprinting, renaturation and modification of proteins, protein fractionation using ultrafiltration (UF), ion liquid separation of bioproducts, reverse micellar extraction, etc. The preparation of bioseparation materials, as well as part of bioseparation process research development in the past 5 years, are introduced here.

Qualitative and quantitative analysis in quality control of traditional Chinese medicines

Separation techniques with high efficiency and sensitive detection have been widely used for quality control of traditional Chinese medicines (TCMs). High-performance liquid chromatography, gas chromatography, and capillary electrophoresis are commonly used to separate various components in TCMs. Ultraviolet detection, fluorescence detection, evaporative light-scattering detection, mass spectrometry and nuclear magnetic resonance can be applied to separation techniques for qualitative and quantitative analysis of TCMs. The development of quality control for TCMs based on quantitative and qualitative analysis from 2000 to 2007 are reviewed; the fingerprint technique is also discussed due to its broad application in the quality control of TCMs. Prospects for further research based on our primary results are also discussed.