Evaluation on Extraction Conditions and HPLC Analysis Method for Bioactive Compounds of Astragali Radix

This study has been conducted to establish the optimal extraction process and HPLC analysis method for the determination of marker compounds as a part of the materials standardization for the development of health functional food materials from Astragali radix. Five extraction conditions including the shaking extraction at room temperature and the reflux extraction at $85^{\circ}C$ with 30%, 50% and 95% ethanol were evaluated. Reflux extraction with 50% ethanol showed the highest extraction yield as $27.27{\pm}2.27%$, while the extraction under reflux with 95% ethanol showed significantly the lowest yield of $10.55{\pm}0.24%$. The quantitative determination methods of calycosin-7-O-${\beta}$-D-glucoside and calycosin as marker compounds of Astragali radix extracts were optimized by HPLC analysis using a Thermo Hypersil column ($4.6{\times}250mm$, $5{\mu}m$) with the gradient elution of water and acetonitrile as the mobile phase at the flow rate of $0.8mLmin^{-1}$ and a detection wavelength of 230nm. The HPLC/UV method was applied successfully to the quantification of two marker compounds in Astragali radix extracts after validation of the method with the linearity, accuracy and precision. The contents of calycosin-7-O-${\beta}$-D-glucoside and calycosin in 50% ethanol extracts by reflux extraction were significantly higher as $1,700.3{\pm}30.4$ and $443.6{\pm}8.4{\mu}g-1$, respectively, comparing with those in other extracts. The results indicate that the reflux extraction with 50% ethanol at $85^{\circ}C$ is optimal for the extraction of Astragali radix, and the established HPLC method are very useful for the evaluation of marker compounds in Astragali radix extracts to develop the health functional material from Astragali radix.

황기의 추출조건 및 유효성분의 HPLC 분석법 평가