title: [Study on extraction of quercetin in guava leaf by microemulsion].
abstract: OBJECTIVE
  To study the extraction of quercetin in guava leaf by microemulsion.
  
  
  METHODS
  The optimal component proportion was obtained by investigating the ratio of oil, water, surfactant and cosurfactant. The extraction of quercetin in microemulsion was determined by HPLC which compared with the traditional method.
  
  
  RESULTS
  The traditional solvent extraction methods were used to extract quercetin in guava leaf, and the content of quercetin extracted with methanol was the highest (4.72 microg/mL). But the contents of quercetin extracted by 72 percent of the microemulsions were higher than methanol, and the extraction by the optimum formulation of microemulsion which consisted of acetoacetate (oil phase) -30% avantin solution (water phase) -RH60 (surfactant) was 2 times as much as that was extracted by methanol (10.43 microg/mL).
  
  
  CONCLUSIONS
  Compared with traditional solvent extraction methods, microemulsion method can effectively improve the extraction rate of quercetin in guava leaf.
authors: Guangzhou University of Chinese Medicine, Guangzhou 510405, China. lulovesmu@yahoo.com.cn
authors: Rui-Xin
authors: RX
authors: Lu
authors: Wen-Biao
authors: WB
authors: Lu
mesh_terms: D019840:2-Propanol / Q000737:chemistry; D000085:Acetates; D004655:Emulsions; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D031647:Psidium / Q000737:chemistry*; D011794:Quercetin / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*; D013501:Surface-Active Agents / Q000008:administration & dosage / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods*
chemical_list: D000085:Acetates; D004655:Emulsions; D013501:Surface-Active Agents; D011794:Quercetin; D019840:2-Propanol