Effect of minimizing amount of template by addition of macromolecular crowding agent on preparation of molecularly imprinted monolith.

One of the main challenges in the preparation of molecularly imprinted polymers (MIPs) is the substantial initial amount of template needed because of the requirement of high load capacities for most applications. A new strategy of macromolecular crowding was suggested to solve this problem by reducing the amount of template in the polymerization recipe. In a ternary porogenic system of polystyrene (PS) (crowding agent), tetrahydrofuran, and toluene, an imprinted monolithic column with high porosity and good permeability was synthesized using a mixture of ellagic acid (template), acrylamide, and ethylene glycol dimethacrylate. The effect of polymerization factors, including monomer-template molar ratio and the molecular weight and concentration of PS, on the imprinting effect of the resulting MIP monoliths was systematically investigated. At a high ratio of monomer-template (120:1), the greatest imprinting factor of 32.4 was obtained on the MIP monolith with the aid of macromolecular crowding agent. The PS-based imprinted monolith had imprinting even at the extremely high ratio of functional monomer to template of 1510:1. Furthermore, an off-line solid-phase extraction based on the ground MIP was conducted, and the purification recovery of ellagic acid from pomegranate-rind extract was up to 80 %. In conclusion, this approach based on macromolecular crowding is simple, and is especially valuable for those applications of MIP preparation for which a rare template is used.

Isolation of three sesquiterpene lactones from the roots of Cichorium glandulosum Boiss. et Huet. by high-speed counter-current chromatography.

Because of the skeletal complexity and similarity of the polarity, little research was reported on the isolation of sesquiterpene lactones by high-speed counter-current chromatography (HSCCC). Herein, three sesquiterpene lactones were successfully purified from the ethyl acetate extract of the roots of the traditional Uyghur medicinal plant Cichorium glandulosum Boiss. et Huet. by HSCCC. The separation was performed in two steps with two solvent systems: n-hexane-ethyl acetate-methanol-water (1.5:5:2.75:5, v/v/v/v) and ethyl acetate-methanol-water (20:1:20, v/v/v). From 166 mg of the ethyl acetate extract, 19 mg of lactucopicrin was isolated with the first solvent system and 10 mg of 11beta,13-dihydrolactucin and 16 mg of lactucin were obtained with the second solvent system. All purified compounds were over 94% purity as determined by HPLC analysis, and these chemical structures were confirmed by (1)H NMR and (13)C NMR.

[Studies on chemical constituents in root of Paeonia sinjiangensis].

OBJECTIVE: To study the chemical constituents of the root of Paeonia sinjiangensis. METHOD: The constituents were isolated by silica column chromatography, and their structures were identified on the basis of spectral analysis and their physical-chemical constants. RESULT: Five compounds, paeoniflorin( I ), albiflorin (II), lactiflorin(III), daucosterol(IV), sucrose (V), were obtained. CONCLUSION: All of the compounds were obtained from this plant for the first time.