[Effect of heating treatment on stability of two coumarins in Angelica dahurica and activity of tyrosinase].

To study the heating treatment of Angelica dahurica under different temperature and time conditions on the stability of coumarins and tyrosinase activity. HPLC method was used to determine the contents of imperatorin and isoimperatorin, and tyrosinase activity was assayed by measuring the oxidation rate of L-DOPA in vitro. After heated, the contents of imperatorin increased. Expect for being heated at 90 ℃ for 2 h, the content of isoimperatorin was higher than crude one. Before and after being heated, A. dahurica showed an activating effect on tyrosinase. In the same temperature and time conditions, the activation rate increased with the rise of concentration of tyrosinase extracts. Heating process for A. dahurica could change the contents of imperatorin and isoimperatorin, mainly increasing their concentrations.