ABSTRACT
Glycyrrhizin is a major bioactive component of liquorice, which exerts multiple biochemical and pharmacological activities and is frequently used in combination with other drugs in the clinic. Mycophenolate mofetil (MMF), an immunosuppressant widely used in transplant patients, is metabolized by UDP-glucuronyltransferases (UGTs). Although significant evidence supports that glycyrrhizin could interact with the cytochrome P450s (CYPs), few studies have addressed its effects on UGTs. The present study aimed at investigating the regulatory effects of diammonium glycyrrhizinate (GLN) on UGTs in vitro and in vivo. We found that long-term administration of GLN in rats induced overall metabolism of MMF, which might be due to the induction of UGT1A protein expression. Hepatic UGT1A activity and UGT1A mRNA and protein expression were significantly increased in GLN-treated rats. UGT1A expression levels were also increased in the intestine, contradicting with the observed decrease in intestinal UGT1A activities. This phenomenon may be attributed to different concentrations of glycyrrhetinic acid (GA) in liver and intestine and the inhibitory effects of GA on UGT1A activity. In conclusion, our study revealed that GLN had multiple effects on the expression and activities of UGT1A isoforms, providing a basis for a better understanding of interactions between GLN and other drugs.
Subject(s)
Animals , Male , Rats , Drugs, Chinese Herbal , Chemistry , Pharmacology , Glucuronosyltransferase , Chemistry , Metabolism , Glycyrrhizic Acid , Chemistry , Pharmacology , Herb-Drug Interactions , Intestines , Chemistry , Kinetics , Liver , Chemistry , Rats, Sprague-DawleyABSTRACT
AIM@#This study was designed to explore the effects of short-term and long-term pretreatment of diammonium glycyrrhizinate (GLN) on the pharmacokinetics of entecavir (ETV) in rats.@*METHODS@#Male SD rats were randomized into short-term and long-term experimental groups, respectively. In the short-term experiment, the control group received saline, the low dose group received GLN 13.5 mg·kg(-1) and the high dose group received GLN 40.5 mg·kg(-1). ETV (0.09 mg·kg(-1)) was given i.g. 0.5 h after saline/GLN administration. For the long-term experiment, rats were allocated into two experimental designs. The control group received saline/ETV (0.09 mg·kg(-1)), the low dose group received GLN 13.5 mg·kg(-1)/ETV 0.09 mg·kg(-1) + GLN 13.5 mg·kg(-1), while the high dose group received GLN 40.5 mg·kg(-1)/ETV 0.09 mg·kg(-1) + GLN 40.5 mg·kg(-1); all administration was continued for 15 days. On the 16(th) day, 0.09 mg·kg(-1) ETV was administrated to all groups. Blood samples were obtained at different time points after ETV administration to determine plasma ETV concentrations.@*RESULTS@#Pretreatment with glycyrrhizin resulted in no significant alterations in the main pharmacokinetic parameters of ETV in the short-term and long-term administration experiments.@*CONCLUSION@#Diammonium glycyrrhizinate has no effect on ETV pharmacokinetics in rats.
Subject(s)
Animals , Male , Rats , Drug Interactions , Glycyrrhizic Acid , Pharmacology , Guanine , Blood , Pharmacokinetics , Rats, Sprague-DawleyABSTRACT
AIM@#To identify and quantify the major metabolites of salvianolic acid B (SAB) after intravenous injection in rats.@*METHODS@#LC-IT/TOF-MS was used to identify the metabolites in rat bile, plasma, and urine; LC-MS/MS was used to quantify the two major metabolites.@*RESULTS@#In rat bile, plasma, and urine, nine metabolites were identified, including methylated metabolites of SAB, lithospermic acid (LSA), the decarboxylation and methylation metabolites of LSA, salvianolic acid S (SAS), and dehydrated-SAS. The t1/2 of monomethyl-SAB and LSA were both very short, and monomethyl-SAB had a larger AUC than LSA in rats.@*CONCLUSION@#Nine metabolites were found, the metabolic pathway was described, and the pharmacokinetic profiles of LSA and monomethyl-SAB were studied, thereby clarifying that methylation was the dominant metabolic pathway for SAB in rats.