The effect of licorice drink on cytochrome P3A6 and P-glycoprotein gene transcription in rabbits

Abstract

Licorice is a widely used herb, and its components interact with a number of drugs. Rifampicin is an antibiotic known to induce some drug metabolizing enzymes and transporters and used in our study as a reference drug. The purpose of this research is to study the effect of licorice drink on the levels of cytochrome P3A6 (CYP3A6) and P-glycoprotein (P-gp) gene transcripts using rabbit as an animal model. Four groups of locally inbred male New Zealand rabbits were used, including two control groups, and two treated groups. One group was given a daily oral dose of licorice drink (4 ml/kg body weight) for one week, while the other group was given a daily oral dose of rifampicin (100 mg/kg body weight) for four days. Messenger RNAs were extracted from hepatic and the proximal (first 10-15 cm) intestinal tissues of the four groups and real-time polymerase chain reaction was conducted on them. The licorice treated group showed a significant induction of hepatic CYP3A6 expression (17.6-fold, p=0.004), and inhibition of intestinal CYP3A6 expression (7.6-fold, p=0.0006). Licorice administration did not affect P-gp expression neither in hepatic nor in intestinal tissues. Rifampicin administration significantly induced hepatic CYP3A6 expression with no significant changes in transcription of intestinal CYP3A6, hepatic and intestinal P-gp. It is concluded that licorice can affect the metabolism of drugs that are CYP3A6 substrates, but it might not affect the transport of drugs dependent on P-gp