title: MICROWAVE-ASSISTED EXTRACTION OF PHENOLIC COMPOUNDS FROM POLYGONUM MULTIFLORUM THUNB. ROOTS.
abstract: BACKGROUND
  The aim of this study was to determine the best extraction conditions for total phenolic content (TPC) and antioxidant capacity (AC) of Polygonum multiflorum Thunb. root using microwave-assisted extraction (MAE).
  
  
  METHODS
  The raw material used was Polygonum multiflorum Thunb. root powder. Five factors such as solvent type, solvent concentrations, solvent/material ratio, extraction time and microwave power were studied; TPC and AC values were determined by the Folin-Ciocalteu method and DPPH free radical scavenging activity measurement, respectively. In addition, studies involved assaying the HPLC test of extracts and SEM of samples.
  
  
  RESULTS
  Optimal results pointed to acetone as the solvent, acetone concentration of 60%, solvent/material ratio of 40/1 (v/w), extraction time of 5 mins and microwave power of 127 W. TPC and AC obtained were approximates 44.3 ±0.13 mg GAE/g DW and 341.26 ±1.54 μmol TE/g DW, respectively. The effect of microwaving on the cell destruction of Polygonum multiflorum Thunb. root was observed by scanning electron microscopy (SEM). Some phenolic compounds were determined by the HPLC method, for instance, gallic acid, catechin and resveratrol.
  
  
  CONCLUSIONS
  These factors significantly affected TPC and AC. We can use acetone as a solvent with microwave-assisted extraction to achieve the best result.
authors.affiliation: Department of Food Technology, Can Tho University, Vietnam.|Institute of Biotechnology and Food Technology, Industrial University of Ho Chi Minh City, Vietnam.
authors.forename: Le Pham Tan
authors.initials: LP
authors.lastname: Quoc
authors.affiliation: Department of Food Technology, Can Tho University, Vietnam.
authors.forename: Nguyen Van
authors.initials: NV
authors.lastname: Muoi
mesh_terms: D000096:Acetone / Q000737:chemistry; D000975:Antioxidants / Q000032:analysis; D002392:Catechin / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D000068676:Fallopia multiflora / Q000737:chemistry*; D005707:Gallic Acid / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D008872:Microwaves; D010936:Plant Extracts / Q000032:analysis*; D018517:Plant Roots / Q000737:chemistry*; D059808:Polyphenols / Q000032:analysis*; D000077185:Resveratrol; D012997:Solvents; D013267:Stilbenes / Q000032:analysis
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D059808:Polyphenols; D012997:Solvents; D013267:Stilbenes; D000096:Acetone; D005707:Gallic Acid; D002392:Catechin; D000077185:Resveratrol
keywords: Polygonum multiflorum Thunb.; Trolox; antioxidant capacity; microwave-assisted extraction; solvent; total polyphenol