title: Microwave-assisted extraction of polysaccharides from Yupingfeng powder and their antioxidant activity.
abstract: BACKGROUND
  Microwave-assisted reflux extraction of polysaccharides YPF-P from the famous Chinese traditional drug, Yupingfeng powder, optimization of extracting conditions and evaluation of their antioxidant activity were conducted in this study.
  
  
  RESULTS
  Single factor effect trends were achieved through yields and contends of YPF-P obtained from different extracting conditions. Then through a three-level, four-variable Box-Behnken design of response surface methodology adopting yield as response, the optimal conditions were determined as follows: Material/solvent ratio 1:23.37, microwave power 560 W, Extraction temperature 64°C, and extraction time 9.62 min. Under the optimal conditions, the YPF-P extraction yield was 3.23%, and its content was detected as 38.52%. In antioxidant assays, the YPF-P was tested to possess 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities with an IC50 value of 0.262 mg/ml. In addition, YPF-P was also proved to have relatively low ferric reducing antioxidant power (FRAP), compared to Vc, through FRAP assay.
  
  
  CONCLUSIONS
  In the microwave assisted reflux extraction research, good YPF-P yield was achieved from materials with relatively low YPF-P content. And for the first time, both DPPH and FRAP assays were conducted on YPF-P, which proved that the antioxidant activity of YPF-P contributed to the functions of this medicine.
authors.affiliation: Department of Medicinal Plants, Agronomy College, Sichuan Agricultural University, Wenjiang Region, Chengdu 611130, P. R. China.
authors.forename: Dan
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Medicinal Plants, Agronomy College, Sichuan Agricultural University, Wenjiang Region, Chengdu 611130, P. R. China.
authors.forename: Bi-Bo
authors.initials: BB
authors.lastname: Zhang
authors.affiliation: Department of Medicinal Plants, Agronomy College, Sichuan Agricultural University, Wenjiang Region, Chengdu 611130, P. R. China.
authors.forename: Xiao-Xia
authors.initials: XX
authors.lastname: Qu
authors.affiliation: Department of Medicinal Plants, Agronomy College, Sichuan Agricultural University, Wenjiang Region, Chengdu 611130, P. R. China.
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.affiliation: Department of Pharmacy, The First Affiliated Hospital of Chengdu Medical College, Xindu Region, Chengdu 610500, P. R. China.
authors.forename: Min-Yong
authors.initials: MY
authors.lastname: Yuan
keywords: Antioxidant activity; Yupingfeng powder; microwave-assisted extraction; polysaccharides; response surface methodology