Microwave-assisted extraction (MAE) technology was used to extract silymarin from milk thistle seeds. The single factor experiment and quadratic orthogonal rotation regression combination design were adopted to study the effects of such factors as extraction time, extraction temperature, ethanol concentration and solid-liquid ratio on silymarin yield. UV-Vis spectrophotometry method was employed to measure the Silybin value. The optimal technological condition of silymarin from milk thistle seeds by MAE was determined, and then the extraction regression mathematical model was established. The order of factors that influence the extraction yield within the experimental model was as follows: ethanol concentration>solid-liquid ratio>extraction temperature>extraction time. The optimum extracting process parameters were obtained as follows: extraction time 50min , extraction temperature 130℃, 85% ethanol concentration (v/v) , solid-liquid ratio 1∶40(g/mL), and under such conditions , experimental value of silymarin yield after extraction three times is 59.33mg/g. The validation experiments verify that the established regression mathematical model can predict the extraction yield of silymarin accurately.

Keywords: microwave-assisted extraction, silymarin yield, optimum extraction parameters
DOI: 10.3965/j.issn.1934-6344.2008.01.075-081
Citation: Wang Xin, Zheng Xianzhe, Liu Chenghai. Optimization of microwave-assisted extraction of silymarin from milk thistle seeds. Int J Agric & Biol Eng. 2008;1(1): 75－81.