Up-regulation on cytochromes P450 in rat mediated by total alkaloid extract from Corydalis yanhusuo

Abstract

Background: Yanhusuo (Corydalis yanhusuo W.T. Wang; YHS), is a well-known traditional Chinese herbal medicine, has been used in China for treating pain including chest pain, epigastric pain, and dysmenorrhea. Its alkaloid ingredients including tetrahydropalmatine are reported to inhibit cytochromes P450 (CYPs) activity in vitro. The present study is aimed to assess the potential of total alkaloid extract (TAE) from YHS to effect the activity and mRNA levels of five cytochromes P450 (CYPs) in rat.

Methods: Rats were administered TAE from YHS (0, 6, 30, and 150 mg/kg, daily) for 14 days, alanine aminotransferase (ALT) levels in serum were assayed, and hematoxylin and eosin-stained sections of the liver were prepared for light microscopy. The effects of TAE on five CYPs activity and mRNA levels were quantitated by cocktail probe drugs using a rapid chromatography/tandem mass spectrometry (LC-MS/MS) method and reverse transcription-polymerase chain reaction (RT-PCR), respectively.

Results: In general, serum ALT levels showed no significant changes, and the histopathology appeared largely normal compared with that in the control rats. At 30 and 150 mg/kg TAE dosages, an increase in liver CYP2E1 and CYP3A1 enzyme activity were observed. Moreover, the mRNA levels of CYP2E1 and CYP3A1 in the rat liver, lung, and intestine were significantly up-regulated with TAE from 6 and 30 mg/kg, respectively. Furthermore, treatment with TAE (150 mg/kg) enhanced the activities and the mRNA levels of CYP1A2 and CYP2C11 in rats. However, the activity or mRNA level of CYP2D1 remained unchanged.

Conclusions: These results suggest that TAE-induced CYPs activity in the rat liver results from the elevated mRNA levels of CYPs. Co-administration of prescriptions containing YHS should consider a potential herb (drug)-drug interaction mediated by the induction of CYP2E1 and CYP3A1 enzymes.

Figure 1

HPLC-fingerprint chromatograms of total alkaloids of YHS. (A) Chromatogram of the total alkaloid extract (TAE); (B) chromatogram of reference standards; and (C) chromatogram of the blank solvent; 1, protopine; 2, allocryptopin; 3, dehydrocorydaline; 4, tetrahydropalmatine; 5, corydaline; 6, tetrahydroberberine;7, glaucine.

Figure 2

Chemical Structure of the main alkaloid components of YHS.

Figure 3

Histopathological examination of liver sections from rats treated with TAE from YHS. Liver sections of male Sprague–Dawley rats treated with various dosages of TAE showed largely normal appearances. For each dosage group, four sections were made, and the microphotos show representative foci in the control rats (A), 6 mg/kg (B), 30 mg/kg (C), and 150 mg/kg (D) TAE-treated rats. Tissues were fixed in formalin and stained with hematoxylin and eosin. Magnification: 200 × .

Figure 4

Relative changes in the gene expression levels of CYP3A1 and CYP 2E1 by TAE from YHS in the rat liver, kidney, lung, and intestine. Rats were treated for 14 days with TAE, phenobarbital (positive control), or 0.5% sodium carboxymethylcellulose solution (control). The mRNA levels of CYP3A1 and CYP2E1 were determined by real-time PCR with the results normalized to those of β-actin (as indicated). Data was expressed as mean ± SD triplicate measurements of five samples. *P < 0.05; **P < 0.01, response significantly increased relative to the control group.

Figure 5

Relative changes in the gene expression levels of CYP1A2, CYP2D1 and CYP2C11 by TAE from YHS in the rat liver, kidney, lung, and intestine. Rats were treated for 14 days with TAE, phenobarbital (positive control), or 0.5% sodium carboxymethylcellulose solution (control). The mRNA levels of CYP1A2, CYP2D1, and CYP2C11 were determined by real-time PCR with the results normalized to those of β-actin (as indicated). Data was expressed as mean ± SD triplicate measurements of five samples. *P < 0.05; **P < 0.01, response significantly increased relative to the control group.