Abstract
Isoliquiritigenin, a chalcone found in licorice has shown a variety of
biological activities including antioxidative, anti-inflammatory,
estrogenic, chemopreventive and antitumor effects. Thus, pharmacokinetics of
isoliquiritigenin and its metabolites [liquiritigenin, glucuronidated
isoliquiritigenin (M1), and glucuronidated liquiritigenin (M2)] after
intravenous and oral administration of isoliquiritigenin was evaluated in
rats. The pharmacokinetics of isoliquiritigenin, liquiritigenin, M1, and M2
showed no dose dependence after both intravenous and oral administration of
isoliquiritigenin. Although approximately 92.0 % of the oral
isoliquiritigenin was absorbed, the extent of the absolute bioavailability
value was only 11.8 % of the oral dose. The low absolute bioavailability
value of isoliquiritigenin might be due to the considerable metabolism of
isoliquiritigenin in the small intestine and liver. This was supported by
the facts that the ratios of AUCM1/AUCisoLQ and
AUCM2/AUCisoLQ were high (over 0.25),
isoliquiritigenin disappeared, and M1 and M2 were formed mainly in S9
fractions of the liver and small intestine. The affinities of
liquiritigenin, isoliquiritigenin, M1, and M2 were high in the liver, small
intestine, large intestine, and/or kidney.
Key words
Glycyrrhiza glabra
- Fabaceae - isoliquiritigenin - liquiritigenin - glucuronidated metabolites - pharmacokinetics
