Assessment of metabolic interaction between curcumin and tramadol using the isolated perfused rat liver

Introduction

The presence of phytochemicals in herbal medicines can lead to herb-drug interactions, altering the levels of these compounds and conventional drugs in the bloodstream by influencing CYP450 activity. Considering curcumin's effect on the CYP enzymes responsible for tramadol metabolism, it is essential to assess the potential interaction between curcumin and tramadol when administered together.

Materials and methods

The pharmacokinetics of tramadol were examined in rats receiving either single or multiple doses of curcumin (80 mg/kg) compared to rats without curcumin treatment. Tramadol liver perfusion was conducted on all rat groups and perfusate samples were collected at specified intervals. Tramadol and its main metabolite were detected using an HPLC system coupled with a fluorescence detector.

Results

Tramadol concentrations were notably higher in the co-administered group compared to both the control and treatment groups. Conversely, lower concentrations of M1 were observed in the co-administered and treatment groups compared to the control group. The AUC0-60 parameters for tramadol were as follows: 32944.8 ± 1355.5, 22925.7 ± 1650.1, and 36548.0 ± 2808.4 ng⋅min/ml for the control, treatment, and co-administered groups, respectively. Both the co-administered and treatment groups exhibited a lower AUC0-60 of M1 compared to the control group. The lack of significant difference in Cmax and AUC0-60 of M1 between the treatment and co-administered groups suggests that single and multiple doses of curcumin have comparable effects on CYP2D6.

Conclusions

These results indicate a potential for drug interactions when curcumin and tramadol are taken together. Furthermore, the influence of curcumin on tramadol metabolism varied between single and multiple oral administrations of curcumin. Hence, it is vital to highlight this interaction in clinical settings and conduct additional research to fully understand the clinical implications of combining curcumin and tramadol.

A phase I study of docetaxel plus synthetic lycopene in metastatic prostate cancer patients

PURPOSE

Our preclinical studies showed that lycopene enhanced the anti-prostate cancer efficacy of docetaxel in animal models. A phase I trial (NCT0149519) was conducted to identify an optimum dose of synthetic lycopene in combination with docetaxel (and androgen blockade [androgen deprivation therapy, ADT]), and to evaluate its effect on the safety and pharmacokinetics of docetaxel in men with metastatic prostate cancer.

METHODS

Subjects were treated with 21-day cycles of 75 mg/m2 docetaxel (and ADT), plus lycopene at 30, 90 or 150 mg/day. A Bayesian model averaging continual reassessment method was used to guide dose escalation. Pharmacokinetics of docetaxel and multiple correlative studies were carried out.

RESULTS

Twenty-four participants were enrolled, 18 in a dose escalation cohort to define the maximum tolerated dose (MTD), and six in a pharmacokinetic cohort. Docetaxel/ADT plus 150 mg/day synthetic lycopene resulted in dose-limiting toxicity (pulmonary embolus) in one out of 12 participants with an estimated probability of .106 and thus was chosen as the MTD. Lycopene increased the AUCinf and Cmax of plasma docetaxel by 9.5% and 15.1%, respectively. Correlative studies showed dose-related changes in circulating endothelial cells and vascular endothelial growth factor A, and reduction in insulin-like growth factor 1R phosphorylation, associated with lycopene therapy.

CONCLUSIONS

The combination of docetaxel/ADT and synthetic lycopene has low toxicity and favourable pharmacokinetics. The effects of lycopene on biomarkers provide additional support for the toxicity-dependent MTD definition.

HIGHLIGHTS

The maximum tolerated dose was identified as 150 mg/day of lycopene in combination with docetaxel/ADT for the treatment of metastatic prostate cancer patients. Small increases in plasma exposure to docetaxel were observed with lycopene co-administration. Mechanistically significant effects were seen on angiogenesis and insulin-like growth factor 1 signalling by lycopene co-administration with docetaxel/ADT.

Omeprazole Induces CYP3A4 mRNA Expression but Not CYP3A4 Protein Expression in HepaRG Cells

Unknown interactions between drugs remain the limiting factor for clinical application of drugs, and the induction and inhibition of drug-metabolizing CYP enzymes are considered the key to examining the drug-drug interaction (DDI). In this study, using human HepaRG cells as an in vitro model system, we analyzed the potential DDI based on the expression levels of CYP3A4 and CYP1A2. Rifampicin and omeprazole, the potent inducers for CYP3A4 and CYP1A2, respectively, induce expression of the corresponding CYP enzymes at both the mRNA and protein levels. We noticed that, in addition to inducing CYP1A2, omeprazole induced CYP3A4 mRNA expression in HepaRG cells. However, unexpectedly, CYP3A4 protein expression levels were not increased after omeprazole treatment. Concurrent administration of rifampicin and omeprazole showed an inhibitory effect of omeprazole on the CYP3A4 protein expression induced by rifampicin, while its mRNA induction remained intact. Cycloheximide chase assay revealed increased CYP3A4 protein degradation in the cells exposed to omeprazole. The data presented here suggest the potential importance of broadening the current DDI examination beyond conventional transcriptional induction and enzyme-activity inhibition tests to include post-translational regulation analysis of CYP enzyme expression.

Safety assessment of herbal supplement components targeting hepatotoxicity and CYP3A4 induction in cell-based assay using HepG2 cells

Herbal supplements can cause hepatotoxicity and drug interactions via hepatic cytochrome P-450 (CYP) in some cases. However, there is no simple and stable cell-based assay to conduct a screening for hepatotoxicity and CYP induction. In the present study, we selected 14 components of the herbal supplement based on our previous reports and investigated the safety of the herbal supplement components focusing on toxicity and CYP3A4 induction in a cell-based assay using HepG2. The toxicity of the components was examined by lactate dehydrogenase (LDH) and cell proliferation assays. Then, the CYP3A4 induction of the components were examined by a reporter assay using reporter vectors of CYP3A4. The vector includes the CYP3A4 proximal promoter (CYP3A4PP) and the xenobiotic-responsive enhancer module (XREM) regions. Luteolin (LU) significantly increased LDH activity and decreased cell proliferation activity that suggests LU may cause toxicity in HepG2 cells. Quercetin (QU) increased the transcriptional activity of CYP3A4 (1.5-fold of control) in the reporter assay. However, the induction of QU was slightly in comparison to the validation of the transcriptional activity of CYP3A4 treated with CYP3A4 inducers. The CYP3A4 induction of QU may not involve CYP3A4PP but involves the XREM response. Throughout our results, the method in the present study may be useful for a safety assessment of herbal supplements, primarily focusing on hepatotoxicity and CYP3A4 induction. PRACTICAL APPLICATION: Even though there are problems with herbal supplements, studies related to toxicity are not actively carried out. The present methods may apply to the safety assessment for herbal supplements and be useful for the prevention and verification of health hazards caused by herbal supplements (the summary is shown in Figure S2).

The effect of lycopene on cytochrome P450 isoenzymes and P-glycoprotein by using human liver microsomes and Caco-2 cell monolayer model

Lycopene is widely used as a dietary supplement. However, the effects of lycopene on cytochrome P450 (CYP) enzymes or P-glycoprotein (P-gp) are not comprehensive. The present study was performed to investigate the effects of lycopene on the CYP enzymes and P-gp activity. A cocktail method was used to evaluate the activities of CYP3A4, CYP2C9, CYP2C19, CYP2D6 and CYP2E1. Caco-2 cell monolayer model was carried out to assay lycopene on P-gp activity. The results indicated that lycopene had a moderate inhibitory effect on CYP2E1, with IC50 value of 43.65 μM, whereas no inhibitory effects on CYP3A4, CYP2C19, CYP2D6 and CYP2E1, with IC50 values all over 100 μM. In addition, lycopene showed almost no inhibitory effect on rhodamine-123 efflux and uptake (p > .05), indicated no effects on P-gp activity. In conclusion, there should be required attention when lycopene are coadministered with other drugs that are metabolised by CYP2E1.

Pharmacokinetic interactions of curcuminoids with conventional drugs: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Herb-drug interactions are of great concern in health practices. Curcumin is a natural polyphenol extracted from turmeric, a spice widely used all over the world. Curcumin is clinically used due to its acceptable safety profile and therapeutic efficacy.

AIM OF THE STUDY

Current paper aims to highlight the effect of curcumin on concomitantly used drugs.

METHODS

Electronic databases including PubMed, Scopus and Science Direct were searched with the keywords "curcumin" in the title/abstract and "drug interaction," "drug metabolism," "cytochrome," "P-glycoprotein" and "P450" in the whole text.

RESULTS

Curcumin can induce pharmacokinetic alterations such as changes in Cmax and AUC when concomitantly used with pharmacological agents like cardiovascular drugs, antidepressants, anticoagulants, antibiotics, chemotherapeutic agents, and antihistamines. The underlying mechanisms of these interactions include inhibition of cytochrome (CYP) isoenzymes and P-glycoprotein. There is only one clinical trial which proved a significant alteration of conventional drugs in concomitant use with curcumin indicating the need for further human studies.

CONCLUSIONS

Although in vitro and in vivo studies do not provide enough evidence to judge the clinical drug interactions of curcumin, physicians must remain cautious and avoid drug combinations which may lead to curcumin-drug interactions.