Objectives : Gwakhyangjeonggi-san (GJS) which consists of 13 herbal medicines has been used to treat gastrointestinal disorders caused by common cold. This study was performed to compare GJS decoctions produced using different pressure levels for various extraction times.Methods : Decoctions were prepared by the pressure levels of 0 kgf/cm 2 (non-pressurized) or 1 kgf/cm 2 (pressurized) for 30-180 min. The extraction yield, total soluble solid content (TSSC), and hydrogen ion concentration (pH) were measured, and the contents of the nine marker compounds were determined using high performance liquid chromatography.Results : The higher pressure and longer extraction time significantly increased TSSC value, while decreased the pH value. However, only extraction time affected the extraction yield of pressurized decoction. Variation of the amounts of chemical compounds was shown in pressurized and non-pressurized decoctions during extraction time. The result of regression analysis showed that pressure and extraction time can influence [1][2][3][4] .In the present study, the extraction yield, total soluble solids content (TSSC), hydrogen ion concentration (pH), and the content of marker compoud were compared through GJS decoctions Preparation of standard solutionsThe standard compounds were accurately weighed and dissolved in methanol to produce stock solutions. Each stock solution was diluted to make working solutions, which were used to construct calibration curves. Preparation of GJS decoctions and samplesThe herbal mixture of GJS (675 g corresponding to one formula set, 'Je' in Korean) were extracted at 100°C in water using a high-speed vacuum of each decoction was measured using a refractometer Commun. 2014) were applied to this study. Statistical analysesTwo-tailed t-tests and Dunnett's test were conducted for the two-group and the multi-group comparisons using Microsoft Excel (Microsoft, Redmond, WA, USA) and SYSTAT 10 (SPSS Inc., Chicago, IL, USA). Differences were considered significant at P < 0.05, P < 0.01, or P < 0.001.Regression analysis was performed through extraction yields, TSSC, pH, and the amount of Table 2. The nine marker compounds of GJS decoction, such as chlorogenic acid, caffeic acid, liquiritin, hesperidin, apigetrin, rosmarinic acid, oxypeucedanin hydrate, byakangelicin, and glycyrrhizin, were well separated on chromatograms by using the methods described above (Fig. 3).Chlorogenic acid and caffeic acid were mainly extracted from P. frutescens var. crispa and rosmarinic acid was extracted from both A. rugosa and P. frutescens var. crispa [8][9][10] . In the pressurized decoctions, the amounts of chlorogenic acid, caffeic acid, and rosmarinic acid were

Objectives : This study was aimed to compare Gyejibokryeong-hwan (GBH) decoctions produced using different pressure levels for various extraction times to find the optimal extraction conditions through extraction yield, total soluble solids content (TSSC), hydrogen ion concentration (pH), and the contents of chemical compounds. Methods : Decoctions of GBH were prepared under the pressure levels of 0 or 1 kgf/㎠ for 30-180 min using water as extraction solvent. The extraction yield, TSSC, and pH were measured, and the amounts of the chemical compounds were determined using high performance liquid chromatography-photodiode array detector. Results : The higher pressure and longer extraction time increased the values of TSSC and extraction yield, while decreased the pH value. The decoctions produced in 180 min by pressurized method and produced in 150 min by non-pressurized method showed maximum values of extraction yield and TSSC with minimum value of pH. The amounts of chemical compounds showed variations in pressurized and non-pressurized decoction during overall extraction times. The influences of pressure and extraction time on extraction yield, TSSC, pH, and the contents of chemical compounds were confirmed by regression analysis, which showed that all extraction values were significantly affected by at least one of two extraction factors, pressure and extraction time. Conclusions : This study suggests that the pressure and extraction time can significantly affect the extraction efficiency of components from GBH decoctions. However, optimal extraction conditions could not be chosen due to the variation of the amounts of chemical compounds.