title: Optimization of Microwave-Assisted Extraction Conditions for Five Major Bioactive Compounds from Flos Sophorae Immaturus (Cultivars of Sophora japonica L.) Using Response Surface Methodology.
abstract: Microwave-assisted extraction was applied to extract rutin; quercetin; genistein; kaempferol; and isorhamnetin from Flos Sophorae Immaturus. Six independent variables; namely; solvent type; particle size; extraction frequency; liquid-to-solid ratio; microwave power; and extraction time were examined. Response surface methodology using a central composite design was employed to optimize experimental conditions (liquid-to-solid ratio; microwave power; and extraction time) based on the results of single factor tests to extract the five major components in Flos Sophorae Immaturus. Experimental data were fitted to a second-order polynomial equation using multiple regression analysis. Data were also analyzed using appropriate statistical methods. Optimal extraction conditions were as follows: extraction solvent; 100% methanol; particle size; 100 mesh; extraction frequency; 1; liquid-to-solid ratio; 50:1; microwave power; 287 W; and extraction time; 80 s. A rapid and sensitive ultra-high performance liquid chromatography method coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (EIS-Q-TOF MS/MS) was developed and validated for the simultaneous determination of rutin; quercetin; genistein; kaempferol; and isorhamnetin in Flos Sophorae Immaturus. Chromatographic separation was accomplished on a Kinetex C18 column (100 mm × 2.1 mm; 2.6 μm) at 40 °C within 5 min. The mobile phase consisted of 0.1% aqueous formic acid and acetonitrile (71:29; v/v). Isocratic elution was carried out at a flow rate of 0.35 mL/min. The constituents of Flos Sophorae Immaturus were simultaneously identified by EIS-Q-TOF MS/MS in multiple reaction monitoring mode. During quantitative analysis; all of the calibration curves showed good linear relationships (R² > 0.999) within the tested ranges; and mean recoveries ranged from 96.0216% to 101.0601%. The precision determined through intra- and inter-day studies showed an RSD% of <2.833%. These results demonstrate that the developed method is accurate and effective and could be readily utilized for the comprehensive quality control of Flos Sophorae Immaturus.
authors.affiliation: Institute of Material Medical Planting, Chongqing Academy of Chinese Materia Medica (Chongqing Engineering Research Center for Fine Variety Breeding Techniques of Chinese Materia Medica, Chongqing Key Laboratory of Chinese Medicine Resources), Chongqing Sub-Center of National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Science, Chongqing 400065, China. liujinliang0827@163.com.|College of Agronomy and Biotechnology, Southwest University, Chongqing 400715, China. liujinliang0827@163.com.
authors.forename: Jin-Liang
authors.initials: JL
authors.lastname: Liu
authors.affiliation: Institute of Material Medical Planting, Chongqing Academy of Chinese Materia Medica (Chongqing Engineering Research Center for Fine Variety Breeding Techniques of Chinese Materia Medica, Chongqing Key Laboratory of Chinese Medicine Resources), Chongqing Sub-Center of National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Science, Chongqing 400065, China. lilongyun8@163.com.
authors.forename: Long-Yun
authors.initials: LY
authors.lastname: Li
authors.affiliation: College of Agronomy and Biotechnology, Southwest University, Chongqing 400715, China. hegh@swu.edu.cn.
authors.forename: Guang-Hua
authors.initials: GH
authors.lastname: He
mesh_terms: D002851:Chromatography, High Pressure Liquid; D019833:Genistein / Q000302:isolation & purification; D044949:Kaempferols / Q000302:isolation & purification; D008516:Medicine, Chinese Traditional; D008872:Microwaves; D010946:Plants, Medicinal / Q000737:chemistry; D011794:Quercetin / Q000031:analogs & derivatives / Q000302:isolation & purification; D012431:Rutin / Q000302:isolation & purification; D029909:Sophora / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry
chemical_list: D044949:Kaempferols; C047368:3-methylquercetin; D012431:Rutin; C006552:kaempferol; D011794:Quercetin; D019833:Genistein
keywords: Flos sophorae immaturus; UHPLC-ESI-Q-TOF MS/MS; microwave-assisted extraction; response surface methodology; simultaneous determination; simultaneous extraction