Acetylation of Rehmannia glutinosa polysaccharides and antioxidant activity of acetylated derivatives / 中国中药杂志

This study aims to acetylate Rehmannia glutinosa polysaccharides by acetic anhydride method, optimize process parameters and evaluate their antioxidant activity. With the degree of substitution(D_s) as a criterion, the effects of reaction time, acetic anhydride-to-polysaccharides ratio and temperature were investigated. Process parameters were optimized by single-factor experiment and response surface methodology. The infrared spectroscopy(IR) and scanning electron microscopy(SEM) proved the successful acetylation and were employed to preliminarily analyze the structural characteristics of acetylated derivatives. The results showed that the D_s was 0.327 under the optimal technological conditions, including m(acetic anhydride):m(R. glutinosa polysaccharides)=2.70, reaction time 3.0 h and temperature 48 ℃. Further, the antioxidant properties of acetylated derivatives were investigated in vitro and acetylation was found effective to improve the antioxidant activity of R. glutinosa polysaccharides. This study provides a reference for the further development and application of R. glutinosa polysaccharides.

Application progress of molecularly imprinted polymers in separation of active ingredients from Chinese materia medica / 中草药

Separation of active ingredients from Chinese materia medica (CMM) by molecularly imprinted polymers has such advantages as high speed, low cost, being reusable, low pollution, and so on. Because of this reason, the synthesis of molecularly imprinted polymers and its application in separation have drawn more and more attention of researchers in the field of CMM all over the world. Obviously, the core of this research is to explore the relationship between the polymer-structure and separation efficiency. Based on the types of active ingredients of CMM (flavone, alkaloids, phenylpropanoids, terpenoids, etc.), the design principle of molecularly imprinted polymer, its preparation methods and latest application in separation of active ingredients from CMM were introduced. Therefore, this paper can provide a reference for designing new materials with higher selectivity in separation of active ingredients from CMM.