Abstract: In this paper the extraction process of polyhydroxystilbenes from Rheum likiangense was investigated by orthogonal experiment with contents of Rhapontin and Desoxyrhaponticin as indexes. Their contents were determined by HPLC. The optimum conditions for extraction are as follows: the solid-liquid ratio 1:12, the temperature 65 ℃, the ethanol content 90%, pH=7, and extraction time 2 h. Under the optimal extract conditions, the total contents of two polyhydroxystilbenes including Rhapontin and Desoxyrhaponticin were 104.98 mg/g.

Key words: Rheum likiangense, polyhydroxystilbenes, extraction process, orthogonal experiment