Abstract
Berberine (Ber) and its main metabolites were identified and quantified using liquid chromatography/electrospray ionization/ion trap mass spectrometry. Rat plasma contained the main metabolites, berberrubine, thalifendine, demethyleneberberine, and jatrorrhizine, as free and glucuronide conjugates after p.o. Ber administration. Moreover, the original drug, the four main metabolites, and their glucuronide conjugates were all detected in liver tissues after 0.5 h and in bile samples 1 h after p.o. Ber administration. Therefore, the metabolic site seemed to be the liver, and the metabolites and conjugates were evidently excreted into the duodenum as bile. The pharmacokinetics of Ber and the four metabolites were determined in conventional and pseudo germ-free rats (treated with antibiotics) after p.o. administration with 40 mg/kg Ber. The AUC0-limt and mean transit time values of the metabolites significantly differed between conventional and pseudo germ-free rats. The amounts of metabolites were remarkably reduced in the pseudo germ-free rats, whereas levels of Ber did not obviously differ between the two groups. The intestinal flora did not exert significant metabolic activity against Ber and its metabolites, but it played a significant role in the enterohepatic circulation of metabolites. In this sense, the liver and intestinal bacteria participate in the metabolism and disposition of Ber in vivo.
Footnotes
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This study was partially supported by a 21st Century of Center of Excellence Program grant from the Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT).
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Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
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doi:10.1124/dmd.106.011361.
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ABBREVIATIONS: Ber, berberine; HPLC, high-performance liquid chromatography; LC/MS, liquid chromatography/mass spectrometry; LC/MS/MS, liquid chromatography/tandem mass spectrometry; ESI, electrospray ionization; M1, berberrubine; M2, thalifendine; M3, demethyleneberberine; M4, jatrorrhizine; TIC, total ion chromatogram; AUC, area under the plasma concentration-time curve; AUMC, area under the first moment curve; MTT, mean transit time; SIM, selective ion monitor.
- Received June 7, 2006.
- Accepted September 5, 2006.
- The American Society for Pharmacology and Experimental Therapeutics
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