Optimization of pretreatment with microwaves prior the pressurized hot water extraction of anthraquinones from Heterophyllaea pustulata, using Doehlert experimental design

Abstract

The effect of the microwave radiation on the stems ofHeterophyllaea pustulatawas studied as a pretreatment to extraction of four anthraquinones with therapeutic potential (soranjidiol, rubiadin, rubiadin 1-methyl ether, 2-hydroxi-3-methyl anthraquinone), using pressurized hot water. With the purpose to achieve optimization of microwave pretreatment and determine the influence of each operational variable (microwave power, irradiation time and particle size range) on the extraction of anthraquinones, response surface methodology involving Doehlert experimental design was applied. It was demonstrated that microwave pretreatment enhance the anthraquinones extraction and the optimal microwave pretreatment conditions were power 445 W, irradiation time 3.50 min and particle size range 590 to < 1190μm.