Study on the extraction methods of emodin from Radix polygoni multiflori

AIM: To establish an extraction method of emodin from Radix polygoni multiflori . METHODS: Emodin in Radix polygoni multiflori was taken as an evaluating marker and determined by HPLC, the effects of different solvents and extraction models on extraction ratio of the emodin were systematically investigated. And also the orthogonal test was further used to optimize extracting conditions. RESULTS: The refluent extraction with 80% alcohol as much as seven times of the medicine amount for 2hs and twice was more effective. CONCLUSION: The kinds of solvent and models of extraction have a great influence upon the extracting efficiency of emodin.