Abstract
Abstract
Introduction:
Herb–drug interaction is an important clinical risk associated with the concomitant consumption of herbal supplements with conventional drugs. African potato (AP) (Hypoxis hemerocallidea) is widely used by HIV and cancer patients as an immune enhancer. In this study, we determined the effects of AP hydroethanolic extract, its ethyl acetate and n-butanol fractions, and four of its major constituents (hypoxhemeroloside A, hypoxoside, acuminoside, and obtuside A) on the key regulator of drug metabolism and transport, namely pregnane X receptor (PXR) and cytochrome P450 enzymes (CYP3A4, CYP2C19, CYP1A2, and CYP2D6) through in vitro methods.
Materials and Methods:
A reporter gene assay was used to determine the activation of PXR. The inhibition of catalytic activity of CYPs was determined using recombinant enzymes. Chemical analysis of AP extract and its fractions was performed by ultra high performance liquid chromatography coupled with mass spectrometry.
Results:
No induction in the PXR transcriptional activity was observed with the AP extract or its constituents. AP extract inhibited CYP2C19, whereas the ethyl acetate fraction inhibited CYP3A4, CYP2C19, and CYP1A2. The n-butanol fraction showed weak inhibition of CYP3A4 and CYP2D6. Among the constituents, hypoxhemeroloside A inhibited CYP2D6 and CYP1A2, whereas obtuside A inhibited CYP2C19 and CYP3A4.
Conclusion:
A lack of PXR activation indicates that H. hemerocallidea does not seem to pose a risk to induce the expression of P-gp and the CYPs mediated by PXR. However, the inhibition of catalytic activity of CYPs by the extract and its constituents may need further attention to assess the drug interaction potential of H. hemerocallidea.
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