| Resveratrol belongs to stilbene compounds,distributed in many plants such as Polygonum cuspidatum,grape and peanut.It has many significant physiological activities such as anti-cancer,anti-bacterial and anti-inflammatory.As a pharmaceutical active ingredient with broad market prospect,it has been widely used in various fields.But due to the content of resveratrol is low in plants and traditional methods for extraction and separation of resveratrol in plants have disadvantages of solvent consumption,serious environmental pollution,complicated operation process,low production rate and so on,it’s urgent to find an efficient,convenient,green and environmentally friendly method for targeted separation resveratrol in plants.It can provide a scientific basis for efficient separation active ingredients in plants.In this paper,molecular imprinted polymers with high selective adsorption ability to target molecule of resveratrol(Res-MIPs)were prepared by using resveratrol as template molecule and functional porous cellulose microspheres as the carrier.The optimal preparation and adsorption conditions of Res-MIPs were determined,and the adsorption mechanism of Res-MIPs was also studied.Finally,the adsorption capacity of Res-MIPs to resveratrol in the extracting solution of Polygonum cuspidatum was studied.The main experimental works and results are as follows:1.The optimal preparation conditions of Res-MIPs were determined and the prepared Res-MIPs was characterized4-vinylpyridine was determined as the optimal functional monomer,ethylene glycol dimethacrylate was determined as the optimal crosslinking agent and acetonitrile was determined as solvent.By optimizing the experimental parameters,1:5:30 was determined as the optimal molar ratio of template molecule,functional monomer and crosslinking agent,3:1 was detennined as the optimal weight ratio of functional monomer and crosslinking agent,65℃ was determined as the optimal reaction temperature.The adsorption capacity of Res-MIPs could reach 10.15 mg/g under the optimal conditions.Res-MIPs was characterized by FT-IR,SEM,TGA and XRD.The result of FT-IR confirmed Res-MIPs was prepared successfully.It could be observed by microstructure of Res-MIPs that it had lots of holes which could specifically identify the template molecule.The result of TGA proved that Res-MIPs had good thermal stability.Morever,the result of XRD showed that Res-MIPs was successfully prepared on the surface of p-CM-MPS and the crystal structure of cellulose was completely preserved during the preparation process.2.The optimal adsorption conditions of Res-MIPs was determined and the adsorption mechanism of Res-MIPs was analyzedThe optimal adsorption condition of Res-MIPs was determined as time 3 h,adsorption temperature 25℃ by the method of control variables,and the adsorption capacity of Res-MIPs was 9.63 mg/g under the optimal conditions.By studying the adsorption kinetics and thermodynamic processes of Res-MIPs,and using models to fit the two adsorption processes,the results showed that the adsorption kinetics process of Res-MIPs was in line with the quasi-secondary adsorption kinetics model,and the adsorption thermodynamic process of Res-MIPs was in line with the Freundlich adsorption isothermal model.In order to study the changes of binding sites during the adsorption process,Scatchard model was used for in-depth analysis of the adsorption data.It was found that the Scatchard fitting curve of Res-MIPs was composed of two straight lines with different slopes,which indicated that there were two kinds of binding sites of high affinity and low affinity during the adsorption process of Res-MIPs.3.The selectivity and reproducibility of Res-MIPs were investigatedThree structural analogues of the resveratrol including piceatannol(Pic),pterostilbene(Pte)and trimethoxystilbene(Tri)were chosen as interfering substances.The adsorption abilities of Res-MIPs to resveratrol were studied in the unit system and multiple system.The experimental results proved that the adsorption capacity of Res-MIPs to resveratrol in unit system and multiple system would not be affected by the interfering substances,its adsorption capacity in the unit system and multiple system were 9.24 mg/g and 8.73 mg/g,respectively.After Res-MIPs were recycled for 5 times,its adsorption capacity could still be maintained more than 90%of the first adsorption cycle,which indicated that the Res-MIPs imprinted material had high recycling performance and could reduce production cost.In summary,resveratrol molecularly imprinted polymers were successfully prepared on porous cellulose microspheres for the first time in this study,and the prepared Res-MIPs had excellent reproducibility and specificity.As the carrier of Res-MIPs,cellulose has many excellent characteristics such as it’s rich in resources,cheap,green and renewable,and the preparation process of Res-MIPs by molecular imprinting technology is relatively simple,which makes this method has the characteristics of both cellulose and molecular imprinting technology.This study not only provides a theoretical basis for the application of cellulose based molecular imprinting technology in drug targeting separation,but also provides a new direction for the development of molecular imprinting technology. |
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