Extraction-condition Optimization of Baicalein and Schisandrin from Hu-gan-kang-yuan Formula Using Orthogonal Array Design

Purpose: To optimize the extraction conditions for Hu-gan-kang-yuan Formula based on extraction rates of baicalein and schisandrin using an orthogonal array design.
Methods: Ethanol concentration (50 - 70 %), ratio of solvent to raw material (8 - 12 mL/g), and extraction time (1 - 3 h) were examined with a three-factor and three-level L9(3)3 orthogonal array design. In addition, analysis of variance (ANOVA) was used to evaluate the statistical significance of the effects of individual factors on extraction rates of baicalein and schisandrin determined by high performance liquid chromatography (HPLC). The number of extractions was further investigated to confirm the extraction rate of target compounds based on the optimized conditions.
Results: The optimized conditions were an ethanol concentration of 70 %; ratio of solvent to raw material, 12:1 mL/g; and extraction time of 60 min. Ethanol concentration and ratio of solvent to raw material showed significant effects on the extraction of the two compounds (p < 0.05). The number of extraction steps, two, was reasonable. The final optimum extraction conditions resulted in 79.48 ± 1.40 and 88.55 ± 1.85 % of extraction for baicalein and schisandrin, respectively.
Conclusion: The optimized extraction conditions for baicalein and schisandrin are practicable and repeatable, and can be upgraded for pilot-scale production of Hu-gan-kang-yuan preparations.

Keywords
Hu-gan-kang-yuan Formula; Extract-condition optimization; Orthogonal array design; Baicalein; Schisandrin