Correlation of molecular weight and nanofiltration mass transfer coefficient of phenolic acid composition from Salvia miltiorrhiza / 中国中药杂志

Based on the molecular sieving and solution-diffusion effect in nanofiltration separation, the correlation between initial concentration and mass transfer coefficient of three typical phenolic acids from Salvia miltiorrhiza was fitted to analyze the relationship among mass transfer coefficient, molecular weight and concentration. The experiment showed a linear relationship between operation pressure and membrane flux. Meanwhile, the membrane flux was gradually decayed with the increase of solute concentration. On the basis of the molecular sieving and solution-diffusion effect, the mass transfer coefficient and initial concentration of three phenolic acids showed a power function relationship, and the regression coefficients were all greater than 0.9. The mass transfer coefficient and molecular weight of three phenolic acids were negatively correlated with each other, and the order from high to low is protocatechualdehyde >rosmarinic acid> salvianolic acid B. The separation mechanism of nanofiltration for phenolic acids was further clarified through the analysis of the correlation of molecular weight and nanofiltration mass transfer coefficient. The findings provide references for nanofiltration separation, especially for traditional Chinese medicine with phenolic acids.

Optimize concentrate process of alkaloid from Leonurus japonicus by ultrafultration-nanofiltration coupling technology / 中国中药杂志

To optimize the concentrate process of alkaloid from Leonurus japonicus by nanofiltration-ultrafiltration coupling technology with response surface methodology. The experiment showed that after ultrafiltration pre-treatment, the total protein removal rate was 94.38% in aqueous extract from L. japonicus, and the nanofiltration technology had obvious advantages over the conventional concentrate process. The optimal concentrate conditions were as follows：molecular weight cut-off 450, pH 3.07, concentration of stachydrine hydrochloride 80.15 mg•L⁻¹, and concentration of the total alkaloid 285.73 mg•L⁻¹. The cut-off rate was 93.37% and 95.85% respectively for stachydrine hydrochloride and the total alkaloid under the optimum conditions, with a relative error of 0.79% and 1.16% respectively. The combination of Box-Behnken design and response surface analysis can well optimize the concentrate process of L. japonicus by nanofiltration, and the results provide the basis for nanofiltration concentrate for heat-sensitive traditional Chinese medicine.