German Chamomile (Matricaria chamomilla) Induces Cytochrome P450 Expression Through Increased BMAL1 Protein Expression in Liver Nuclei

German chamomile (Matricaria chamomilla) is a medicinal herb that promotes improved digestion and reduces insomnia. Although it is widely used worldwide, the mechanism of induction of drug-metabolizing enzymes is unknown. We found that German chamomile extracts induced cytochrome P450 expression at the transcriptional stage. Cyp3a11 expression is decreased at night in wild-type mice, but German chamomile extract induced nocturnal Cyp3a11 and Cyp1a2 expression. German chamomile extract increased the nuclear protein expression of the clock gene BMAL1, which drives and abolishes the rhythm of Cyp3a11 expression. By contrast, German chamomile extract did not significantly alter clock gene expression in the suprachiasmatic nucleus (SCN). Similarly, it did not affect the mRNA expression of the clock genes in the kidneys. Because it did not induce the mRNA expression of ATP-binding cassette (ABC) transporters (Abcb1a, Abcc2, Abcc4, and Abcg2) in the kidney, German chamomile extract had no effect on the transcription of pharmacokinetics-related molecules other than CYPs. German chamomile extract promoted liver-selective nuclear transfer rhythm changes in clock genes and induced the expression of CYPs. This study may help to explain the mechanism of drug interactions associated with chronic German chamomile extract consumption.