COMPARISON OF INFRARED-ASSISTED EXTRACTION AND OTHER TECHNIQUES FOR ANALYSIS OF INDIGO AND INDIRUBIN IN LEAVES OF ISATIS INDIGOTICA FORT

In this study, an infrared-assisted extraction (IRAE) method, in which infrared (IR) radiation was employed to extract the active compounds from plant, was developed and coupled with high performance liquid chromatography (HPLC) for determination of indigo and indirubin in leaves of Isatis indigotica Fort. (Chinese name Daqingye). This newly developed and optimized IRAE method was compared with microwave-assisted extraction (MAE), Soxhell extraction (SE) and ultrasound assisted extraction (UAE) in terms of extraction amounts of these two active components. Under the optimized conditions, the extraction time for IRAE, MAE, SE, and UAE was 20min, 7 min, 12 hr, and 90 min, respectively. Although the extraction lime of IRAE was a little more than that of MAE, it was greatly reduced compared to SE and UAE. For indigo, the amount obtained by these four extraction procedures were: IRAE> MAE> SE> UAE; for indirubin, the amounts obtained were: SE> IRAE> MAE> UAE. Due to the considerable saving of time, high extraction efficiency, low cost, and safety, IRAE has a great potential for offering an alternative technique for extraction of active components from plants.