Ultrafast Vacuum-Assisted Ultrasonic Extraction for Quercetin Quantification in Three Herbal Medicines

An ultrafast workflow-coupling vacuum-assisted ultrasonic extraction (VAUE) with high-performance liquid chromatography (HPLC) was established for quantification of free quercetin in Panax notoginseng (Burk.) F. H. Chen, Crataegus pinnatifida Bunge and Astragalus membranaceus (Fisch.) Bunge. Single-factor experiments were performed to screen suitable extraction conditions. The selected extraction conditions were 60% ethanol as extraction solvent, vacuum-assisted ultrasonic extraction time of 5 min, and liquid/solid ratio of 1:30. The whole analytical procedure for each Panax notoginseng (Burk.) F. H. Chen powder sample, starting from the initiation of ultrasonic extraction, followed by centrifugation, filtration, and HPLC separation, could be completed within 15 min, with recoveries ranging from 78.60% to 110.04%. Compared with conventional extraction methods, VAUE exhibited higher extraction efficiency and shorter extraction time. This relatively simple, cost-effective and mild-condition method offers the possibility of high-throughput quantification of quercetin in Panax notoginseng (Burk.) F. H. Chen, Crataegus pinnatifida Bunge, and Astragalus membranaceus (Fisch.) Bunge, showing potential for preliminary quality assessment of these herbal materials and providing technical support for the exploitation of herbal raw materials and their derivatives.