The influence of soybean extract on the expression level of selected drug transporters, transcription factors and cytochrome P450 genes encoding phase I drug-metabolizing enzymes

Objective: Soybean phytoestrogens, such as genistein and daidzein, reduce climacteric symptoms and the risk of certain chronic diseases such as cancer and cardiovascular diseases. Despite their widespread use in functional foods and dietary supplements, there is very little data available on their safety and herb-drug interactions, especially with antineoplastic agents. Hence, the aim of our study was to assess the effects of soybean extracts on the expression level of CYP genes and their transcriptional factors. We also investigated the effect of soybean on the mRNA level of transporters, such as P-glycoprotein (MDR1) and multidrug resistance-associated proteins (MRP1, MRP2). Materials and methods: Wistar rats were fed a standardized soybean extract (100 mg/kg, p.o.). cDNA was synthesized from total RNA isolated from different tissues (liver and intestinal epithelium) using reverse transcription. Gene expression level was analyzed by RT-PCR method. Results: We demonstrated a significant increase of CYP1A1 mRNA level (by 89%, p=0.002 and 125%, p=0.004) as compared with the control group. An increase of AHR and CAR expression after 10 days was also observed (by 60%, p0.05, respectively). Additionally, an inductive effect for CYP2D1 by 22% (p=0.008), Mdr1a by 267% (