Background: The human placenta metabolizes many endogenous substances, drugs, and xenobiotics. Cytochrome P450 family 1 (CYP1) is expressed in both early- and full-term placenta. The Thai medicinal plant Pueraria candollei var. mirifica (PM) is traditionally consumed for rejuvenation and has neuroprotective, anti-osteoporotic, and antioxidant activities.
Objectives: The objective of this study was to compare the effects of PM and the CYP1A inducer β-naphthoflavone (BNF) on the expression of CYP1, aryl hydrocarbon receptor (AHR), AHR nuclear translocator (ARNT), and the transporter ABCG2.
Materials and Methods: Human choriocarcinoma BeWo cells were treated with BNF (10 μM), ethanolic extract of PM (PM-EtOH), or column chromatographic fractions of PM-EtOH (F2, F4, and F6) at 1, 10, and 100 μg/mL for 24 h. The mRNA expression of target genes was determined using real-time quantitative polymerase chain reaction. The activity of ethoxyresorufin-O-deethylase (EROD), a marker for CYP1, was measured at the RNA harvesting time point.
Results and Discussion: PM-EtOH, F2, and F4 significantly induced EROD activity and expression of CYP1A1 and CYP1A2 while CYP1B1 and AHR were slightly suppressed and ARNT was unchanged. ABCG2 was slightly induced by F2. Therefore, the expression of CYP1 in BeWo cells appears to be independent of the AHR/ARNT regulatory pathway.
Conclusion: The use of PM-containing products at high quantities or for long periods during pregnancy is of concern due to likely herb–drug interactions and toxicological risks through activation of CYP1A1 and CYP1A2 transcription.
Keywords: Cytochrome P450, ethoxyresorufin-O-deethylase, nuclear receptor, placenta, transporter