Studies on extracting free anthraquinone in Rhubarb with alkali extraction

OBJECTIVE To optimize the extraction of the free anthraquinone from the rhubarb with alkali extraction.METHODS Impregnation method,recirculating method and supersonic waves method were compared.Taking content of the free anthraquinone as parameters,the optimum extraction process was selected with the L_9(34)orthogonal design,and factors and levels of extraction technology on influencing the free anthraquinone with alkali extraction was studied.RESULTS The optimum extraction process with alkali extraction was:in 20℃,adding 15-fold times of 2% Na_2CO_3 solution and extracting for 30 minutes for 2 times.CONCLUSION Extracting the free anthraquinone with alkali extraction was feasible.