Studies on Thermal Stability of Ginsenosides Aqueous Solution from the Stem and Leaf of Ginseng and Calculate the Term of Validity

Abstract:

Objective:The influence of heating time and temperature on the content of ginsenosides from stems and leaves of ginseng during water decoction process was researched to calculate the term of validity. Method: The HPLC was used to determine the content of ginsenoside Rg₁ and ginsenoside Re extracted in different heating conditions.An Agilent Extend-C₁₈ column(4.6 mm×250 mm, 5 μm) was used with acetonitrile-water(19∶81)as the mobile phase at the flow rate of 1.0 mL·min^-1,and the column temperature was maintained at 30 ℃ and the detection wavelength was set at 203 nm. The term of validity was caculated by classical homeothermia. Result: When the heat comes to 12 h, ginsenoside Rg₁ and ginsenoside Re had different degree of degradation, and they degraded rapidly when temperature is at 100 ℃. It’s only 20 percent of the initial content at 100 ℃,and 60% at 80 ℃, 80% at 60 ℃.With simple linear regression analysis to 1/T as lgK, the regression equations are:lgK=-2 396.2/T+5.587 3 for ginsenoside Rg1, lgK=-2 518.2/T+5.901 6 for ginsenoside Re. The term of validity of ginsenoside Rg₁ and ginsenoside Re were calculated as 30.1 h and 37.6 h. Conclusion: The content of ginsenoside Rg₁ and ginsenoside Re decreased with time increasing and temperature increasing. The term of validity about stems and leaves of Panax ginseng is in short period.So,intermediate which contains water extract of stems and leaves of P. ginseng should accomplish the preparation within the term of validity.