Abstract: This study was carried out to optimize the hot water extraction of total flavonoids from madder root. The effects of 4 process parameters including ethanol concentration, material-to-liquid ratio, temperature and extraction duration on extraction efficiencywere investigated by one-factor-at-a-time method and orthogonal array design. The results form the one-factor-at-a-time experiments showed that the optimal extraction conditions were 50% aqueous ethanol as extraction solvent at a material-to-liquid ratio of 1:40 (g/mL), temperature 70℃ and extraction duration 2.5 h. The results from the subsequent orthogonal array design experiments indicated that the highest extraction efficiency (1.67%) for madder root was achieved after 2 h of extraction with 60% aqueous ethanol at 70 ℃ and a material-to-liquid ratio of 1:40 (g/mL). In conclusion, the optimized extraction process is simple and feasible and has great reference value.

Key words: madder, total flavanoids, extraction