Molecular docking to understand the metabolic behavior of GNF-351 by CYP3A4 and its potential drug–drug interaction with ketoconazole

In vitro inhibitory effects of cepharanthine on human liver cytochrome P450 enzymes

Context: Cepharanthine (CEP) extracted from the roots of Stephania cepharantha Hayata (Menispermaceae), has a range of therapeutic potential in clinical conditions. Whether it affects the activity of human liver cytochrome P450 (CYP) enzymes remains unclear.Materials and methods: The effects of CEP (100 μM) on eight human liver CYP isoforms (i.e., 1A2, 3A4, 2A6, 2E1, 2D6, 2C9, 2C19 and 2C8) were investigated in vitro using human liver microsomes (HLMs) with specific probe actions and probe substrates. In addition, the enzyme kinetic parameters were calculated.Results: The results showed that the activity of CYP3A4, CYP2E1 and CYP2C9 was inhibited by CEP, with IC₅₀ values of 16.29, 25.62 and 24.57 μM, respectively, but other CYP isoforms were not affected. Enzyme kinetic studies showed that CEP was not only a non-competitive inhibitor of CYP3A4 but also a competitive inhibitor of CYP2E1 and CYP2C9, with Ki values of 8.12, 11.78 and 13.06 μM, respectively. Additionally, CEP is a time-dependent inhibitor for CYP3A4 with K_I/K_inact value of 10.84/0.058 min/μM.Discussion and conclusions: The in vitro studies of CEP with CYP isoforms indicate that CEP has the potential to cause pharmacokinetic drug interactions with other co-administered drugs metabolized by CYP3A4, CYP2E1 and CYP2C9. Further clinical studies are needed to evaluate the significance of this interaction.

Synthesis of Spin-Labelled Bergamottin: A Potent CYP3A4 Inhibitor with Antiproliferative Activity

Bergamottin (BM, 1), a component of grapefruit juice, acts as an inhibitor of some isoforms of the cytochrome P450 (CYP) enzyme, particularly CYP3A4. Herein, a new bergamottin containing a nitroxide moiety (SL-bergamottin, SL-BM, 10) was synthesized; chemically characterized, evaluated as a potential inhibitor of the CYP2C19, CYP3A4, and CYP2C9 enzymes; and compared to BM and known inhibitors such as ketoconazole (KET) (3A4), warfarin (WAR) (2C9), and ticlopidine (TIC) (2C19). The antitumor activity of the new SL-bergamottin was also investigated. Among the compounds studied, BM showed the strongest inhibition of the CYP2C9 and 2C19 enzymes. SL-BM is a more potent inhibitor of CYP3A4 than the parent compound; this finding was also supported by docking studies, suggesting that the binding positions of BM and SL-BM to the active site of CYP3A4 are very similar, but that SL-BM had a better ∆G_bind value than that of BM. The nitroxide moiety markedly increased the antitumor activity of BM toward HeLa cells and marginally increased its toxicity toward a normal cell line. In conclusion, modification of the geranyl sidechain of BM can result in new CYP3A4 enzyme inhibitors with strong antitumor effects.

Pterostilbene supplements carry the risk of drug interaction via inhibition of UDP-glucuronosyltransferases (UGT) 1A9 enzymes

Pterostilbene (PT) is a natural stilbene common in small berries and food supplements, possessing numerous pharmacological activities. However, whether PT can affect the activities of UDP-glucuronosyltransferases (UGT) enzymes remains unclear. The aim of the present study was to investigate the effect of PT on UGT activities and to quantitatively evaluate the food-drug interaction potential due to UGT inhibition. Our data indicated that PT exhibited potent inhibition against HLM, UGT1A6, UGT1A9, UGT2B7, and UGT2B15, moderate inhibition against UGT1A1, UGT1A3, UGT1A8, and UGT2B4, negligible inhibition against UGT1A4, UGT1A7, UGT1A10, and UGT2B17. Further kinetic investigation demonstrated that PT exerted potent noncompetitive inhibition 4-MU glucuronidation by UGT1A9, with IC₅₀ and K_i values of 0.92 μM and 0.52 ± 0.04 μM, respectively. Quantitative prediction study suggested that coadministration of PT supplements at 100 mg/day or higher doses may result in at least a 50% increase in the AUC of drugs predominantly cleared by UGT1A9. Thus, the coadministration of PT supplements and drugs primarily cleared by UGT1A9 may result in potential drug interaction, and precautions should be taken when coadministration of PT supplements and drugs metabolized by UGT1A9.

In vitro inhibitory effects of kaempferitrin on human liver cytochrome P450 enzymes

Context: Kaempferitrinis (KF) is a bioactive flavonoid and possesses numerous pharmacological activities. However, whether KF affects the activity of human liver cytochrome P450 (CYP) enzymes remains unclear. Objective: This study investigates the effects of KF on eight major CYP isoforms in human liver microsomes (HLMs). Materials and methods: In vitro, HLMs were used to investigate the inhibitory effects of KF (100 μM) on the eight human liver CYP isoforms (i.e., 1A2, 3A4, 2A6, 2E1, 2D6, 2C9, 2C19, and 2C8), and corresponding probe substrates were used. Enzyme kinetic studies (0-50 μM of KF) were conducted to determine the inhibition mode of KF on CYP enzymes. Results: The results showed that KF inhibited the activity of CYP1A2, 3A4, and 2C9, with IC₅₀ values of 20.56, 13.87, and 14.62 μM, respectively, but that other CYP isoforms were not affected. Enzyme kinetic studies showed that KF was not only a noncompetitive inhibitor of CYP3A4, but also a competitive inhibitor of CYP1A2 and 2C9, with Ki values of 7.11, 10.24, and 7.58 μM, respectively. In addition, KF is a time-dependent inhibitor for CYP3A4 with K_I/K_inact value of 10.85/0.036 min/μM. Discussion: The in vitro studies of KF with CYP isoforms indicate that KF has the potential to cause pharmacokinetic drug interactions with other co-administered drugs metabolized by CYP1A2, 3A4, and 2C9. Conclusion: It is recommended that KF should not be used with other drugs metabolized by CYP1A2, 3A4, and 2C9. Further clinical studies are needed to evaluate the significance of this interaction.

In vitro inhibitory effects of sophocarpine on human liver cytochrome P450 enzymes

1. Sophocarpine is a biologically active component isolated from the foxtail-like sophora herb and seed that is often orally administered for the treatment of cancer and chronic bronchial asthma. However, whether sophocarpine affects the activity of human liver cytochrome P450 (CYP) enzymes remains unclear. 2. In this study, the inhibitory effects of sophocarpine on the eight human liver CYP isoforms (CYP1A2, 3A4, 2A6, 2E1, 2D6, 2C9, 2C19, and 2C8) were investigated in vitro using human liver microsomes (HLMs). 3. The results indicate that sophocarpine could inhibit the activity of CYP3A4 and 2C9, with the IC₅₀ values of 12.22 and 15.96 μM, respectively, but that other CYP isoforms were not affected. Enzyme kinetic studies showed that sophocarpine is not only a noncompetitive inhibitor of CYP3A4 but also a competitive inhibitor of CYP2C9, with K_i values of 6.74 and 9.19 μM, respectively. Also, sophocarpine is a time-dependent inhibitor of CYP3A4 with K_inact/K_I value of 0.082/21.54 μM^-1min^-1. 4. The in vitro studies of sophocarpine with CYP isoforms suggested that sophocarpine has the potential to cause pharmacokinetic drug interactions with other co-administered drugs metabolized by CYP3A4 and 2C9. Further clinical studies are needed to evaluate the significance of this interaction.

In vitro inhibitory effects of bergenin on human liver cytochrome P450 enzymes

CONTEXT

Bergenin, isolated from the herb of Bergenia purpurascens (Hook. f. et Thoms.) Engl., has anti-inflammatory, antitussive, and wound healing activities. However, whether bergenin affects the activity of human liver cytochrome P450 (CYP) enzymes remains unclear.

MATERIALS AND METHODS

In this study, the inhibitory effects of bergenin (100 μM) on the eight human liver CYP isoforms (i.e., 1A2, 3A4, 2A6, 2E1, 2D6, 2C9, 2C19 and 2C8) were investigated, enzyme kinetics and time-dependent inhibition studies were also performed in vitro using human liver microsomes (HLMs).

RESULTS

The results showed that bergenin inhibited the activity of CYP3A4, 2E1 and 2C9, with IC₅₀ values of 14.39, 22.83 and 15.11 μM, respectively, but other CYP isoforms were not affected. Enzyme kinetic studies showed that bergenin was not only a non-competitive inhibitor of CYP3A4, but also a competitive inhibitor of CYP2E1 and 2C9, with K_i values of 7.71, 11.39 and 8.89 μM, respectively. In addition, bergenin is a time-dependent inhibitor for CYP3A4 with K_inact/K_I value of 0.025/3.50 μM^-1min^-1.

DISCUSSION AND CONCLUSIONS

The in vitro studies of bergenin with CYP isoforms indicate that bergenin has the potential to cause pharmacokinetic drug interactions with other co-administered drugs metabolized by CYP3A4, 2E1 and 2C9. Further clinical studies are needed to evaluate the significance of this interaction.

In vitro inhibitory effects of Friedelin on human liver cytochrome P450 enzymes

CONTEXT

Friedelin is a triterpenoid with several biological activities. However, the affects of Friedelin on the activity of human liver cytochrome P450 (CYP) enzymes remains unclear.

OBJECTIVE

This study investigates the inhibitory effects of Friedelin on the major human liver CYP isoforms (CYP3A4, 1A2, 2A6, 2E1, 2D6, 2C9, 2C19 and 2C8).

MATERIALS AND METHODS

First, the inhibitory effects of Friedelin (100 μM) on the eight human liver CYP isoforms were investigated in vitro using human liver microsomes (HLMs), and then enzyme inhibition, kinetic studies, and time-dependent inhibition studies were conducted to investigate the IC₅₀, K_i and K_inact/K_I values of Friedelin.

RESULTS

The results indicate that Friedelin inhibited the activity of CYP3A4 and 2E1, with the IC₅₀ values of 10.79 and 22.54 μM, respectively, but other CYP isoforms were not affected. Enzyme kinetic studies showed that Friedelin is not only a noncompetitive inhibitor of CYP3A4, but also a competitive inhibitor of CYP2E1, with K_i values of 6.16 and 18.02 μM, respectively. In addition, Friedelin is a time-dependent inhibitor of CYP3A4 with K_inact/K_i value of 4.84 nM/min.

DISCUSSION AND CONCLUSION

The in vitro studies of Friedelin with CYP isoforms suggested that Friedelin has the potential to cause pharmacokinetic drug interactions with other co-administered drugs metabolized by CYP3A4 and 2E1. Further clinical studies are needed to evaluate the significance of this interaction.

In vitro inhibitory effects of pristimerin on human liver cytochrome P450 enzymes

1.Pristimerin (PTM) is a biological component isolated from Chinese herbal plant Celastrus and Maytenus spp. and it possesses numerous pharmacological activities. However, whether PTM affects the activity of human liver cytochrome P450 (CYP) enzymes remains unclear. 2.In this study, the inhibitory effects of PTM on the eight human liver CYP isoforms (i.e. 1A2, 3A4, 2A6, 2E1, 2D6, 2C9, 2C19 and 2C8) were investigated in vitro using human liver microsomes (HLMs). 3.The results showed that PTM inhibited the activity of CYP1A2, 3A4 and 2C9, with IC ₅₀ values of 21.74, 15.88 and 16.58 μM, respectively, but that other CYP isoforms were not affected. Enzyme kinetic studies showed that PTM was not only a non-competitive inhibitor of CYP3A4, but also a competitive inhibitor of CYP1A2 and 2C9, with K_i values of 7.33, 11.60 and 8.09 μM, respectively. In addition, PTM is a time-dependent inhibitor for CYP3A4 with K_inact /K_I value of 0.049/11.62 μM^-1min^-1. 4.The in vitro studies of PTM with CYP isoforms indicate that PTM has the potential to cause pharmacokinetic drug interactions with other co-administered drugs metabolized by CYP1A2, 3A4 and 2C9. Further clinical studies are needed to evaluate the significance of this interaction.

Drug-drug interation prediction between ketoconazole and anti-liver cancer drug Gomisin G

BACKGROUND

Gomisin G, isolated from herb Schisandra chinensis, exhibits anti-tumor activities. Therefore, Gomisin G is a drug candidate for anti-liver cancer therapy.

AIMS

To predict the metabolic behavior and metabolism-based drug-drug interaction of gomisin G.

METHODS

Molecular docking method was used. The crystal structure of CYP3A4 with the ligand ketoconazole was chosen from protein data bank (http://www.rcsb.org/pdb). Chemdraw software was used to draw the two-dimensional structure of gomisin G with standard bond lengths and angles.

RESULTS

Gomisin G can be well docked into the activity site of CYP3A4, and distance between gomisin G the heme active site was 2.75 Å. To evaluate whether the inhibitors of CYP3A4 can affect the metabolism of gomisin G, co-docking of gomisin G and ketoconazole was further performed. The distance between ketoconazole and activity center (2.10 Å) is closer than the distance between gomisin G and activity center of CYP3A4, indicating the easy influence of CYP3A4's strong inhibitor towards the metabolism of gomisin G.

CONCLUSION

Gomisin G is a good substrate of CYP3A4, and CYP3A4 inhibitors easily affect the metabolism of Gomisin G.

Metabolic behavior prediction of pazopanib by cytochrome P450 (CYP) 3A4 by molecular docking

Metabolism-mediated drug adverse effects (e.g., drug-drug interaction, bioactivation, etc.) strongly limit the utilization of clinical drugs. The present study aims to predict the metabolic capability of cytochrome P450 (CYP) 3A4 toward pazopanib which is an excellent drug exhibiting therapeutic role toward various cancers especially for ovarian cancer. Pazopanib can be well docked into the activity cavity of CYP3A4, and the interaction structure in pazopanib was methyl group located besides nitrogen in the five-membered ring. The distance between the hydrogen atom in methyl group and active center is 3.64 Å. The interaction amino acid is Glu374. Furthermore, both pazopanib and ketoconazole were docked into the activity cavity of CYP3A4 to compare their binding potential. The distance between ketoconazole and activity center (2.10 Å) is closer than the distance between pazopanib and activity center of CYP3A4, indicating the easy influence of CYP3A4 inhibitor toward the metabolism of pazopanib. All these data were helpful for the clinical application of pazopanib, and R&D of other tinib drug candidates as new anti-tumor drugs.