Herb⁻Drug Interaction Potential of Anti-Borreliae Effective Extracts from (Samento) and (Banderol) Assessed In Vitro.

Samento (extract from ) and Banderol (extract from ) have been demonstrated to have anti-inflammatory and antimicrobial properties, e.g., against different morphological forms of . However, there is hardly any data on the pharmacological safety of these two herbal medicines. This in vitro study aimed at scrutinizing their possible characteristics as perpetrators in pharmacokinetic herbal⁻drug interactions. Inhibition of cytochrome P450 enzymes (CYPs) was quantified by commercial kits and inhibition of drug transporters by use of fluorescent probe substrates. Induction was quantified by real-time RT-PCR and activation of pregnane x receptor (PXR) and aryl hydrocarbon receptor (AhR) by reporter gene assays. Organic anion transporting polypeptide 1B1 (OATP1B1) (IC = 0.49 ± 0.28%) and OATP1B3 (IC = 0.65 ± 0.29%) were potently inhibited by Banderol, but only weakly by Samento. CYP3A4 was inhibited about 40% at a Samento concentration of 1%. Samento significantly induced mRNA expression of , , , , and and strongly activated PXR, but hardly AhR. In conclusion, the perpetrator profiles of Samento and Banderol for herb⁻drug interactions completely differ. Clinical studies are strongly recommended to clarify whether the effects observed in vitro are of clinical relevance.