Simultaneous quantification of multiple licorice flavonoids in rat plasma.

Abstract

Flavonoids are important naturally occurring polyphenols with antioxidant properties. In this study, we report the development of a liquid chromatography tandem mass spectrometry (LC-MS/MS)-based method capable of simultaneously quantifying multiple active licorice flavonoids (including liquiritin apioside, liquiritin, liquiritigenin, isoliquiritin apioside, isoliquiritin, and isoliquiritigenin) in plasma. Electrospray ionization was used to efficiently generate precursor deprotonated molecules of all the analytes and the [M-H]- ions were used to produce characteristic product ions for MS/MS analysis. We found that inclusion of a very low concentration of HCOONH4 (0.01 per thousand) in the LC mobile phase dramatically improved the detection limit for the tested flavonoids and decreased the interference by matrix effects, which have been referred to as "LC-electrolyte effects." Liquid-liquid extraction with ethyl acetate was effective for isolation of all the analytes and resulted in the lowest matrix effects of several tested sample cleanup methods. This bioanalytical method showed good linearity between 0.32 ng/mL and 1 microg/mL analyte in 50-microL plasma samples. The accuracy and precision at different analyte concentrations varied from 85 to 110% and from 0.8 to 8.8%, respectively. Finally, we demonstrated the applicability of this method in a pilot pharmacokinetic study of rats receiving an oral dose of Xiaochaihu-tang, an important Chinese herbal remedy for chronic hepatitis. The use of a low concentration of HCOONH4 in the LC mobile phase could be used to improve LC-mass spectroscopy- or LC-MS/MS-based methods.

• Authors: Li Li, Shipiao Liang, Feifei Du, Chuan Li
• Journal: Journal of the American Society for Mass Spectrometry (J Am Soc Mass Spectrom) Vol. 18 Issue 4 Pg. 778-82 (Apr 2007) ISSN: 1044-0305 [Print] United States
• PMID: 17291779 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Validation Study)

Chemical References

• Drugs, Chinese Herbal
• Flavonoids
• shosaiko-to

Topics

• Administration, Oral
• Animals
• Chromatography, High Pressure Liquid
• Drugs, Chinese Herbal (pharmacokinetics)
• Flavonoids (blood)
• Glycyrrhiza (chemistry)
• Rats
• Reproducibility of Results
• Spectrometry, Mass, Electrospray Ionization (methods)
• Tandem Mass Spectrometry