Effect of harvest times on yield and quality of Isatidis Folium in Longzhong semi-arid region

Different harvest times of Isatidis Folium had a significant effect on the yield and the quality of Isatidis Radix and Isatidis Folium. The harvest could increase the yield of Isatidis Folium, but reduce the yield of Isatidis Radix, the quality of Isatidis Radix and Isatidis Folium. One, two and three harvests of the Isatidis Folium reduced the yield of Isatidis Radix as 18.3%, 58.6%, 67.4% and increased the yield of the Folium as 107.3%, 86.3% and 116.6%. Ethanol-soluble extract of Isatidis Radix was 42.50%, 42.24%, 31.77%, which were 1.19%, 1.79%, 26.13% lower than those of the control, respectively. The water-soluble extract, indirubin, indigo content reduced with increase of the harvest times. Indirubin contents with two or three times harvests were higher than that of the control, but the content of water-soluble extract, ethanol-soluble extract, indigo were lower than those of the control.