Optimization of extraction conditions for active components in Hypericum perforatum using response surface methodology

Optimal conditions for extraction of Hypericum perforatum were determined u sing response surface methodology. A 3 x 4 x 4 full factorial design repres enting three extraction temperatures, four extraction times, and four solve nt concentrations was executed. The overall extraction efficiency was defin ed by comparing either the total extractable material weight or the individ ual component peak area to the peak area of luteolin as internal standard. Of the tested variables, the extraction temperature most significantly affe cted extraction efficiency. Higher temperatures gave better extraction effi ciencies, but high temperature also caused decomposition of hypericin. With in the test range, responses for most variables had local maxima. Optimum r anges of time and concentration for individual variables were overlaid. Con sidering all variables, optimum ranges for extraction time and extraction s olvent concentration (percent ethanol in acetone) were 5.0-6.7 h and 44-74% at 23 degrees C, 5.4-6.9 h and 45-72% at 40 degrees C, and 5.3-5.9 h and 4 4-69% ethanol in acetone at 55 degrees C, respectively.