Study on the extraction and purification of ferulic acid in Angelica sinensis

The ferulic acid is one of the main active components in Angelica sinensis (Danggui), and the microwave-assisted extraction was used for the extraction of ferulic acid from Danggui. The operation technological conditions of the microwave-assisted extraction were optimized by single factor experiments and uniform design method. The optimized technological parameters found are as follows: The 90% ethanol is used as solvent, the ratio of solvent to solid material is 6:1 (mL:g), soak time is 30 min, the microwave irradiation time is 9 min and the microwave power is 850 W. Using the above optimum parameters, the extraction yield reaches 70.19% and the ferulic acid content in the dry powder obtained from the extraction of Danggui is 0.212%, these values are higher than that obtained by traditional heat-water (80°C) extraction and ultrasonic extraction method. The extraction time needed for microwave-assisted extraction is only 3/40 of that needed for heat-water extraction and is 3/10 of that needed for ultrasonic extraction method. Furthermore, using the high-speed counter-current chromatography (HSCCC) with the solvent system of n-hexane-ethyl acetate-methanol-water (3:7:5:5, v/v), the dry powder obtained from the extraction of Danggui was purified and the ferulic acid with purity of 98.2% was obtained. The purity mentioned was assayed by HPLC and its chemical structure was confirmed by using Mass and 1H-NMR.