[Study on dynamic changes and stability of effective components of Arnerbia euchroma]

By studying on the factors influencing the dynamic changes of shikonin and its derivant,to interpret the great loss of these components in concentrating process of percolate of Arnerbia euchroma.

By sampling dynamically,and using HPLC for detection, dynamic changes of 5 components of shikonin and its derivant and relative factors were investigated during concentrating process at 50 degrees C, and influence of three key factors including temperature,pH and ethanol content on these components' stability were further investigated through single factor and multiple factors tests.

The content of 5 major components lost greatly during concentrating process, with volume and ethanol content decrease continually and pH from 5.56 to 4.5. Single factor and multiple factors tests about three key factors including temperature, pH and ethanol content indicated that these 5 components remained stable for 6 hours under condition of 40-60 degrees C, pH 3-7 and ethanol content 35%-70%. However,these components will precipitatie when the ethanol content of percolate became very low, which led to much lower content results and "loss phenomenon" of shikonin and its derivant.

The true causes for "great loss" of shikonin and its derivant during concentrating process do not lie in their chemical transformation due to poor stability, but lie in continual precipitation of these liposoluble components during concentrating process, which leads to content decrease significantly.