Extraction optimization of total flavonoids from Polygonum amplexicaule var. sinense by orthogonal test

Objective To optimize the extraction technology of total flavonoids from Polygonum amplexicaule var. sinense. Methods The extraction technology of total flavonoids was optimized by orthogonal test using ethanol concentration, ethanol ratio, extracting time, and extracting times as factors with the extraction of total flavone and extract yield as indexes. Results The optimal extraction technology was as follows: 10-folds of 70% ethanol, extracting for three times, and 1.5 h each time. Conclusions The optimal technology is stable and feasible for the extraction of total flavonoids from P. amplexicaule var. sinense.