Transformation of rare ginsenoside Compound K from ginsenoside Rb1 catalyzed by snailase immobilization onto microspheres / 中草药

Objective: To prepare snailase immobilization onto microspheres and to optimize the process conditions for the transformation of rare ginsenoside Compound K (CK) from ginsenoside Rb1 (Rb1) catalyzed by snailase immobilization onto microspheres. Methods: Considering the recovery rate of enzyme activity as the target, crosslink-embedding method was used for preparing the snailase immobilization onto microspheres and optimizing the preparation technology by orthogonal test. Furthermore, the enzyme characterization of temperature, enzymatic properties of pH value, thermal stability, pH stability, and storage stability was studied, and the effectiveness of temperature, concentration reaction time, and transformational times on the bioconversion rate was studied to optimize the preparation conditions. Results: The best process was achieved at 2% sodium alginate, 2% CaCl2, SiO2 and snail enzyme mass ratio of 1:1, with the above conditions, the enzyme activity recovery rate was 81.94%, immobilization snailase and free snailase exhibit different properties about thermal stability and pH stability, the optimum temperature was 60℃, and the optimum pH was 5.0. Under these conditions, the snailase immobilization onto microspheres remained 55.17% enzyme activity when storaged at 15℃ for 30 d. The best process was achieved at 55℃, the substrate concentration was 1.0 mg/mL, the conversion time was 36 h, the effective continuous transformational times were five rounds and the average transformational ratio for rare ginsenoside CK was up to 36.79%. Conclusion: The results concluded from the experiments indicate that the immobilization procedure could promote the resistance of enzyme against temperature, pH shift, and some other tough reaction conditions, meanwhile prolong the enzymatic lifetime for storage. The bioconversion rate is impoved and it is feasible to prepare rare ginsenoside CK by enzymolysis with snailase immobilization onto microspheres. Besides, the condition is moderate and it is suitable for industrialization.

Ultrasound assisted the enzymolysis of ginsenosides to prepare pare ginseng saponin Compound K / 中国中药杂志

To prepare ginseng saponin Compound K with ultrasound-assisted total zymolytic ginseng saponins. The conversion rate was taken as the index to detect the pre-treatment factors such as ultrasonic power and ultrasonic time, as well as the impact of enzymatic factors, such as pH value, temperature, concentration of substrate, dosage of enzyme and reaction time, on the conversion rate. The response surface method was used to optimize the preparation conditions. The enzymolytic products were identified with MS, 1H-NMR and 13C-NMR. The results showed that the optimum conditions of the ultrasound-assisted enzymolysis were 250 W for ultrasonic power, 15 min for ultrasonic time, 5.5 for enzymolytic pH, 50 degrees C for enzymolytic temperature, 36 h for enzymolytic time, 4:5 for enzymolytic dosage: substrate and 1.0 g x L(-1) for concentration of substrate. The relative molecular mass of reaction products was 622.4. Therefore, the nuclear magnetic map verified that the reaction product was rare ginseng saponin Compound K. Under the above conditions, based on the total zymolytic ginseng saponins, the conversion rate of rare ginseng saponin Compound K was 6.91% in proportion to the total of ginsenosides. The process features gentle reaction conditions, high conversion rate and simple and reliable process, which is suitable for industrial production.

Study on preparation and in vitro characteristics of ginsenoside Rg3 binary solid dispersion / 中国中药杂志

With low molecular weight chitosan and poloxamer 188 as the joint carriers, ginsenoside Rg3 solid dispersions were prepared by using the solvent evaporation method for an in vitro dissolution test. Subsequently, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray diffraction (X-RD) were adopted for a phase analysis. The results showed that the 60 min in vitro cumulative dissolution rate of ginsenoside Rg3 solid dispersions prepared with low molecular weight chitosan and poloxamer 188 at the ratio of 2:1 exceeded 90%, and the drug was dispersed in carriers in an amorphous state. Therefore, ginsenoside Rg3 solid dispersions prepared with low molecular weight chitosan and poloxamer 188 could help significantly improve the drug dissolution, with a practical application value.