[Study on extraction of quercetin in guava leaf by microemulsion].
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.
Lu
Rui-Xin
RX
Guangzhou University of Chinese Medicine, Guangzhou 510405, China. lulovesmu@yahoo.com.cn
Lu
Wen-Biao
WB
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*
D000085:Acetates; D004655:Emulsions; D013501:Surface-Active Agents; D011794:Quercetin; D019840:2-Propanol