title: Development of a hyphenated procedure of heat-reflux and ultrasound-assisted extraction followed by RP-HPLC separation for the determination of three flavonoids content in Scutellaria barbata D. Don.
abstract: A hyphenated procedure of heat-reflux and ultrasound-assisted extraction (HUAE), and an accurate high-performance liquid chromatographic (HPLC) method were developed for the determination of apigenin, baicalin and luteolin content in Scutellaria barbara D. Don. The suitable HUAE conditions for the extraction of target compounds from the herb were identified as an ultrasonic frequency of 40kHz, power of 185W, duty cycle of 75% (intermittent sonication), mean particle size of 0.355mm, extraction temperature of 50°C, ratio of solvent to raw material of 12:1 (mL/g), ethanol concentration of 60% (v/v), extraction time of 30min and three cycles. Compared with a traditional heat-reflux extraction method, the proposed method reduced the extraction time, extraction temperature and solvent consumption. Also, this HUAE method achieved superior apigenin, baicalin and luteolin yields. Furthermore, the developed HUAE-HPLC method was applied successfully for the simultaneous evaluation of three bioactive compounds in five samples of S. barbara D. Don obtained from different geographical regions. These results clearly demonstrated that the combined HUAE-HPLC process is feasible in the future commercialized manufacture of this highly valuable Chinese herbal medicine.
authors.affiliation: Department of Environmental Engineering & Science, Chia Nan University of Pharmacy and Science, Tainan 71710, Taiwan.
authors.forename: Ming-Chi
authors.initials: MC
authors.lastname: Wei
authors.forename: Yu-Chiao
authors.initials: YC
authors.lastname: Yang
authors.forename: Hui-Fen
authors.initials: HF
authors.lastname: Chiu
authors.forename: Show-Jen
authors.initials: SJ
authors.lastname: Hong
mesh_terms: D005591:Chemical Fractionation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D056148:Chromatography, Reverse-Phase / Q000379:methods*; D000431:Ethanol / Q000737:chemistry; D005419:Flavonoids / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D057230:Limit of Detection; D016014:Linear Models; D010316:Particle Size; D010936:Plant Extracts / Q000737:chemistry; D015203:Reproducibility of Results; D031363:Scutellaria / Q000737:chemistry*; D013010:Sonication; D013696:Temperature
chemical_list: D005419:Flavonoids; D010936:Plant Extracts; D000431:Ethanol
keywords: Apigenin; Baicalin; HPLC; Luteolin; Scutellaria barbata D. Don; Ultrasound-assisted extraction