Figure 3.

The addition of β-G (0.125 U/mL) and α-R (0.45 U/mL) during the making of the tea increased the release of ginkgo flavonoids and ginkgolides. Ginkgo tea (4 g) was put into a heat preservation cup, 200 mL boiling water was added into the same cup and kept warm for 15 min. α-R was added and kept at 65 °C for 1 h, then β-G was added and kept at 90 °C for 1 h. Tea infusion of the first time was collected by filtration. An amount of 200 mL boiling water was added into the residue of Ginkgo tea and kept warm for 15 min for the second time. Tea infusion of the second time was collected by filtration. The above step was repeated for the third time, and the tea infusion of the third time was collected by filtration. The experiments in the control group were taken with the same steps except without enzyme addition. Before HPLC detection, the tea infusion was concentrated and dried, then dissolved in methanol. (A) The total flavonoid content in the tea infusion of each time was determined by HPLC-UV analysis. (B) The total flavonoid content in the Ginkgo tea, the tea infusion, and the tea residue after three times of brewing were determined by HPLC-UV analysis. (C) The total flavonoids released from the Ginkgo tea during three times of brewing were compared between the control and enzyme treatment groups. (D) The ginkgolide content in the tea infusion of each time was determined by HPLC-ELSD analysis. (E) The ginkgolide content in the Ginkgo tea, the tea infusion, and the tea residue after three times of brewing were determined by HPLC-ELSD analysis. (F) The total ginkgolides released from the Ginkgo tea during three times of brewing were compared between control and enzyme treatment group. Data are mean ± SD of three independent experiments. Data are mean ± SD of three independent experiments. * p < 0.05, ** p < 0.01 vs. control.