Separation and Purification of Bamboo Leaf Flavones by Polyvinylpolypyrrolidone Adsorption.

In view of the adsorption performance of polyvinylpolypyrrolidone (PVPP) to flavones, the adsorption and purification of bamboo leaf flavones (BLFs) by PVPP were studied. The flavones solution was adsorbed by PVPP column chromatography, and then establish a relatively effective method for elution and purification of flavones from bamboo leaf. The optimal separation conditions of column chromatography were determined as the following: the feed concentration of 10 mg/mL, the ratio of diameter to height of 1:1.9, eluents of deionized water (21 mL) and 70% ethanol (800 mL) with a flow rate of 0.33 mL/min. The purity of flavones obtained from ethanol eluents (80-480 mL) was 96.2%. This showed that the PVPP had an ideal adsorption and purification effect on BLFs.

Catalytic esterification performance of protease in micro-aqueous system.

OBJECTIVE: To evaluate the catalytic esterification performance of proteases in micro-aqueous systems and to study the suitable conditions for maintaining protease activity. RESULTS: It was found that the protease showed better enzyme catalytic activity in the micro-aqueous phase containing 4% boric acid-borax buffer than that of the pure organic phase. The protease activity was easily activated by 0.20 M boric acid-borax buffer, and the enzyme activity was still high for a long time in alkaline environment (pH 8.40-9.60) and under the temperature of 40-55 °C. Experiments using protease and Candida lipase to synthesize sucrose-6-ethyl ester showed that protease had better esterification activity than Candida lipase in the micro-aqueous phase.

Study on the relationship between crosslinking degree and properties of TPP crosslinked chitosan nanoparticles.

In order to reveal the relationship between the degree of crosslinking and the properties of chitosan nanoparticles, a potassium polyvinyl sulfate (PVSK) titration method was established for the determination of free amino group in chitosan, which showed that there was a window effect in the crosslinking degree and particle size of three kinds of molecular weight chitosan cross-linked by different content of tripolyphosphate (TPP), and the nanoparticles with moderate crosslinking degree were smaller. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) showed the moderate degree of cross-linking nanoparticles had strong antibacterial properties. IR analysis showed that the interaction between chitosan nanoparticles with different crosslinking degree and TPP were different. X-ray diffraction analysis showed that the cross-linked chitosan nanoparticles were amorphous. Above all, the crosslinking degree of TPP cross-linked chitosan nanoparticles was related to the particle size and antibacterial properties.

Preparation and characterization of crosslinked porous starch hemostatic.

In order to develop starch hemostatic materials with excellent hemostatic properties, the preparation of crosslinked porous starch (SPS) with sodium trimetaphosphate (STMP) as cross-linking agent was studied in this paper. When the solid-liquid ratio of porous starch (PS) was 30%, the mass ratio of cross-linking agent to starch was 0.04-1, and the SPS was crosslinked at pH 10.0, 55 °C for 50-60 min, the water absorption ratio and swelling ratio of SPS reach up to 160.5% and 239.1%, respectively. The characterization by infrared spectra, scanning electron microscopy and X-Ray diffraction spectra confirmed that the structure of SPS is similar to that of PS. The degradation experiment in vitro indicated that the degradation effect of PS was better than that of SPS. The whole blood coagulation kinetics experiment showed that SPS could promote the formation of blood clot, and the adsorption experiment of red blood cells in vitro showed that SPS could adsorb red blood cells. The average hemostasis time of SPS in tail amputation 1 cm and liver laceration were 181.03 s and 179.30 s.

Study the effect of trypsin enzyme activity on the screening of applying frontal affinity chromatography.

Frontal affinity chromatography (FAC) combined with enzyme has been widely used for drug screening. In this paper, the effect of target enzyme activity on screening of bioactive compounds was studied through applying FAC. Trypsin with different degree of inactivation were prepared as target enzyme by thermal denaturation. Their primary structure was identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and use Fourier transform infrared (FTIR) and ultraviolet-visible (UV-vis) spectroscopy to detect group structure. Ultimately, it was found that the main structure of enzyme with decreased activity remained unchanged. The oxymatrine and matrine which can interact with trypsin were selected to study their binding to trypsin with different activities in FAC. The results showed that oxymatrine and matrine had a significant difference in the breakthrough volume among seven kinds of columns prepared by trypsins with different activities, at the different concentration. It indicated that trypsins with different activities in FAC could combine with oxymatrine and matrine. The binding constant (Kd) variation between oxymatrine, matrine and trypsin with different activities are 5.520 ±â€¯0.038 and 3.577 ±â€¯0.071, within error range, which indicated that the activity of target enzyme with primary unchanged structure has no effect on screening of bioactive components by FAC.