In vivo effect of Kaempferia parviflora extract on pharmacokinetics of acetaminophen

Black ginger extract and its active compound, 5,7-dimethoxyflavone, increase intestinal drug absorption via efflux drug transporter inhibitions

Black ginger is used as an herbal medicine for self-care and health promotion. Black ginger extract has been shown to alter the function of transporters in several cell types. This study demonstrates the interaction between the extract and 5,7-dimethoxyflavone (DMF) on drug efflux mediated by breast cancer resistance proteins (BCRP) and P-glycoprotein (P-gp) in Caco-2 cells and heterologous cell systems [Madin-Darby canine kidney type II (MDCKII) stably transfected with human BCRP (MDCKII/BCRP) or human P-gp (MDCKII/P-gp)]. The transepithelial flux of ³H-Digoxin and ³H-Estrone sulfate, prototypic substrates of P-gp, and BCRP, respectively, across Caco-2 cell monolayers, MDCKII/BCRP, and MDCKII/P-gp cells were determined. The results demonstrate that black ginger extract (10 μg/ml) significantly increases ³H-Digoxin and ³H-Estrone sulfate transport from the apical to basolateral side while decreasing transport from the basolateral to apical side of Caco-2 cells and MDCKII cell overexpression of BCRP or P-gp. The effect of the extract on ³H-Digoxin and ³H-Estrone sulfate transport was related to a decrease in efflux ratio. Likewise, DMF (5 μM) significantly increased ³H-Digoxin and ³H-Estrone sulfate absorption with a decreased efflux ratio compared to the control. Interestingly, the extract also significantly increased absorption of paclitaxel, an anti-cancer drug, which has poor oral absorption. Taken together, co-administration of drugs as substrates of BCRP and P-gp, with the black ginger extract containing DMF, might alter the pharmacokinetic profiles of the medicine.

Pharmacokinetic and pharmacodynamic herb-drug interactions of common over-the-counter pain medications

Pain is one of the most common reasons for seeking medical intervention, and self-medication with over-the-counter medications and/or traditional herbal remedies has become increasingly popular. In this review, original articles on understanding possible herb-drug interactions between traditional herbs and four major pain medications-acetaminophen, aspirin, ibuprofen and naproxen-are compiled and analyzed. In terms of analytical methods, high-performance liquid chromatography using an isocratic eluent system coupled to biological sample clean-up is the most common, while a wide variety of detectors have been observed, including a photodiode array, variable wavelength detector, electrochemical detector and tandem mass spectrometer. Both synergistic and anti-synergistic effects were observed for acetaminophen and aspirin, while only synergistic effects have been found for naproxen. Currently, no interactions have been reported for ibuprofen.

In vitro study on the effect of cornin on the activity of cytochrome P450 enzymes

Background

Cornin is a commonly used herb in cardiology for its cardioprotective effect. The effect of herbs on the activity of cytochrome P450 enzymes (CYP450s) can induce adverse drug-drug interaction even treatment failure. Therefore, it is necessary to investigate the effect of cornin on the activity of CYP450s, which can provide more guidance for the clinical application of cornin.

Methods

Cornin (100 μM) was incubated with eight isoforms of CYP450s, including CYP1A2, 2A6, 3A4, 2C8, 2C9, 2C19, 2D6, and 2E1, in pooled human liver microsomes. The inhibition model and corresponding parameters were also investigated.

Results

Cornin exerted significant inhibitory effect on the activity of CYP3A4, 2C9, and 2E1 in a dose-dependent manner with the IC₅₀ values of 9.20, 22.91, and 14.28 μM, respectively (p < 0.05). Cornin inhibited the activity of CYP3A4 non-competitively with the Ki value of 4.69 μM, while the inhibition of CYP2C9 and 2E1 by cornin was competitive with the Ki value of 11.31 and 6.54 μM, respectively. Additionally, the inhibition of CYP3A4 by cornin was found to be time-dependent with the K_I/K_inact value of 6.40/0.055 min^− 1·μM^− 1.

Conclusions

The inhibitory effect of cornin on the activity of CYP3A4, 2C9, and 2E1 indicated the potential drug-drug interaction between cornin and drugs metabolized by these CYP450s, which needs further investigation and validation.