In vitro effect of pachymic acid on the activity of Cytochrome P450 enzymes

Pachymic acid modulates sirtuin 6 activity to alleviate lipid metabolism disorders

Pachymic acid (Pac), a major bioactive constituent of Poria cocos, is an antioxidant that inhibits triglyceride (TG) accumulation. To the best of our knowledge, the present study investigated for the first time whether Pac activated sirtuin 6 (SIRT6) signaling to alleviate oleic acid (OA)-palmitic acid (PA)-induced lipid metabolism disorders in mouse primary hepatocytes (MPHs). In the present study, MPHs challenged with Pac were used to test the effects of Pac on intracellular lipid metabolism. Molecular docking studies were performed to explore the potential targets of Pac in defending against lipid deposition. MPHs isolated from liver-specific SIRT6-deficient mice were subjected to OA + PA incubation and treated with Pac to determine the function and detailed mechanism. It was revealed that Pac activated SIRT6 by increasing its expression and deacetylase activity. Pa prevented OA + PA-induced lipid deposition in MPHs in a dose-dependent manner. Pac (50 µM) administration significantly reduced TG accumulation and increased fatty acid oxidation rate in OA + PA-incubated MPHs. Meanwhile, as per the results of molecular docking and relative mRNA levels, Pac activated SIRT6 and increased SIRT6 deacetylation levels. Furthermore, SIRT6 deletions in MPHs abolished the protective effects of Pac against OA + PA-induced hepatocyte lipid metabolism disorders. The present study demonstrated that Pac alleviates OA + PA-induced hepatocyte lipid metabolism disorders by activating SIRT6 signaling. Overall, SIRT6 signaling increases oxidative stress burden and promotes hepatocyte lipolysis.

Evaluation of Zuo-Gui Yin Decoction Effects on Six CYP450 Enzymes in Rats Using a Cocktail Method by UPLC-MS/MS

Background. Zuo-Gui Yin Decoction (ZGYD), a traditional Chinese prescription, is mainly used in various kinds of andrology and gynecology diseases. However, the study on the interaction of ZGYD and drugs has not been reported. Therefore, evaluating the interaction between ZGYD and metabolic enzymes is helpful to guide rational drug use. Objective. This study was conducted to explore the effects of ZGYD on the activity and mRNA expressions of six Cytochrome P450 (CYP450) enzymes in rats and to provide a basis for its rational clinical use. Methods. Sprague-Dawley rats were randomly divided into control, ZGYD high, medium, and low-dose group ( $n=6$ ). The concentrations of six probe substrates in plasma of rats in each group were determined by UPLC-MS/MS. In addition, RT-PCR and Western blot were used to determine the effects of ZGYD on the expression of CYP450 isoforms in the liver. Results. Compared with the control group, the main pharmacokinetic parameters AUC(0-t), AUC (0~∞), of omeprazole, dextromethorphan, and midazolam in the high-dose group were significantly decreased, while the CL of these were significantly increased. The gene expressions of CYP2C11 and CYP3A1 were upregulated in the ZGYD medium, high-dose group. The protein expression of CYP2C11 was upregulated in the high-dose group, and the protein expression of CYP3A1 was upregulated in the medium, high-dose group. Conclusion. The results showed that ZGYD exhibited the induction effects on CYP2C11 and CYP3A1 (CYP2C19 and CYP3A4 in humans) in rats. However, no significant change in CYP1A2, CYP2B1, CYP2C7, and CYP2D2 activities was observed. It would be useful for the safe and effective usage of ZGYD in clinic.

Pharmacological profiles and therapeutic applications of pachymic acid (Review)

Poria cocos is a saprophytic fungus that grows in diverse species of Pinus. Its sclerotium, called fu-ling or hoelen, has been used in various traditional Chinese medicines and health foods for thousands of years, and in several modern proprietary traditional Chinese medicinal products. It has extensive clinical indications, including sedative, diuretic, and tonic effects. Pachymic acid (PA) is the main lanostane-type triterpenoid in Poria cocos. Evidence suggests that PA has various biological properties such as cytotoxic, anti-inflammatory, antihyperglycemic, antiviral, antibacterial, sedative-hypnotic, and anti-ischemia/reperfusion activities. Although considerable advancements have been made, some fundamental and intricate issues remain unclear, such as the underlying mechanisms of PA. The present study aimed to summarize the biological properties and therapeutic potential of PA. The biosynthetic, pharmacokinetic, and metabolic pathways of PA, and its underlying mechanisms were also comprehensively summarized.

Impact of Drug Metabolism/Pharmacokinetics and their Relevance Upon Traditional Medicine-based anti-COVID-19 Drug Research

BACKGROUND

The representative anti-COVID-19 herbs, i.e. Poria cocos, Pogostemon, Prunus, and Glycyrrhiza plants, are commonly used in the prevention and treatment of COVID-19, a pandemic caused by SARS-CoV-2. Diverse medicinal compounds with favorable anti-COVID-19 activities are abundant in these plants, and their unique pharmacological/pharmacokinetic properties are being revealed. However, the current trends of drug metabolism/pharmacokinetic (DMPK) investigations of anti-COVID-19 herbs have not been systematically summarized.

METHODS

Here, the latest awareness, as well as the perception gaps of DMPK attributes, in the anti-COVID-19 drug development and clinical usage was elaborated and critically commented.

RESULTS

The extracts and compounds of P. cocos, Pogostemon, Prunus, and Glycyrrhiza plants show distinct and diverse absorption, distribution, metabolism, excretion and toxicity (ADME/T) properties. The complicated herb-herb interactions (HHIs) and herb-drug interactions (HDIs) of anti-COVID-19 Traditional Chinese Medicine (TCM) herb pair/formula dramatically influence the PK/pharmacodynamic (PD) performance of compounds thereof, which may inspire researchers to design innovative herbal/compound formulas for optimizing the therapeutic outcome of COVID-19 and related epidemic diseases. The ADME/T of some abundant compounds in anti-COVID-19 plants have been elucidated, but DMPK studies should be extended to more compounds of different medicinal parts, species and formulations, and would be facilitated by various omics platforms and computational analyses.

CONCLUSION

In the framework of systems pharmacology and pharmacophylogeny, the DMPK knowledge base would promote the translation of bench findings into the clinical practice of anti-COVID-19, and speed up the anti-COVID-19 drug discovery and development.

Baicalein inhibits the pharmacokinetics of simvastatin in rats via regulating the activity of CYP3A4

CONTEXT

Baicalein and simvastatin possess similar pharmacological activities and indications. The risk of their co-administration was unclear.

OBJECTIVE

The interaction between baicalein and simvastatin was investigated to provide reference and guidance for the clinical application of the combination of these two drugs.

MATERIALS AND METHODS

The pharmacokinetics of simvastatin was investigated in Sprague-Dawley rats (n = 6). The rats were pre-treated with 20 mg/kg baicalein for 10 days and then administrated with 40 mg/kg simvastatin. The single administration of simvastatin was set as the control group. The rat liver microsomes were employed to assess the metabolic stability and the effect of baicalein on the activity of CYP3A4.

RESULTS

Baicalein significantly increased the AUC_(0-t) (2018.58 ± 483.11 vs. 653.05 ± 160.10 μg/L × h) and C_max (173.69 ± 35.49 vs. 85.63 ± 13.28 μg/L) of simvastatin. The t_1/2 of simvastatin was prolonged by baicalein in vivo and in vitro. The metabolic stability of simvastatin was also improved by the co-administration of baicalein. Baicalein showed an inhibitory effect on the activity of CYP3A4 with the IC₅₀ value of 12.03 μM, which is responsible for the metabolism of simvastatin.

DISCUSSION AND CONCLUSION

The co-administration of baicalein and simvastatin may induce drug-drug interaction through inhibiting CYP3A4. The dose of baicalein and simvastatin should be adjusted when they are co-administrated.

Pharmacokinetic study on the interaction between pachymic acid and bavachin and its potential mechanism

CONTEXT

Pachymic acid and bavachin are commonly used drugs in the therapy of lung cancer.

OBJECTIVE

The co-administration of pachymic acid and bavachin was investigated to evaluate their potential drug-drug interaction.

MATERIALS AND METHODS

The pharmacokinetics of bavachin (10 mg/kg) was studied in male Sprague-Dawley (SD) rats in the presence of pachymic acid (5 mg/kg) (n = 6). The rats without pre-treatment of pachymic acid were set as the control and the pre-treatment of pachymic acid was conducted for 7 days before the administration of bavachin. The effect of pachymic acid on the activity of CYP2C9 was also estimated in rat liver microsomes with corresponding probe substrates.

RESULTS

Pachymic acid influenced the pharmacokinetic profile of bavachin with the increased AUC (32.82 ± 4.61 vs. 19.43 ± 3.26 μg/L/h), the prolonged t_1/2 (3.21 ± 0.65 vs. 2.32 ± 0.28 h), and the decreased CLz/F (307.25 ± 44.35 vs. 523.81 ± 88.67 L/h/kg) in vivo. The metabolic stability of bavachin was enhanced by pachymic acid and the transport of bavachin was inhibited by pachymic acid. Pachymic acid was found to inhibit the activity of CYP2C9 with the IC₅₀ of 21.25 µM as well as the activity of P-gp.

DISCUSSION AND CONCLUSION

The interaction between pachymic acid and bavachin results from the inhibition of CYP2C9 and P-gp. The dose of bavachin should be adjusted when combining with pachymic acid. The study design can be generalized to a broader study population with adjustment in the dose.

In vitro inhibitory effect of obtusofolin on the activity of CYP3A4, 2C9, and 2E1

Background

Obtusofolin is the major active ingredient of Catsia tora L., which possesses the activity of improving eyesight and protecting the optic nerve. Investigation on the interaction of obtusofolin with cytochrome P450 enzymes (CYP450s) could provide a reference for the clinical application of obtusofolin.

Methods

The effect of obtusofolin on the activity of CYP450s was investigated in the presence of 100 μM obtusofolin in pooled human liver microsomes (HLMs) and fitted with the Lineweaver–Burk plots to characterize the specific inhibition model and kinetic parameters.

Results

Obtusofolin was found to significantly inhibited the activity of CYP3A4, 2C9, and 2E1. In the presence of 0, 2.5, 5, 10, 25, 50, and 100 μM obtusofolin, the inhibition of these CYP450s showed a dose-dependent manner with the IC₅₀ values of 17.1 ± 0.25, 10.8 ± 0.13, and 15.5 ± 0.16 μM, respectively. The inhibition of CYP3A4 was best fitted with the non-competitive inhibition model with the K_i value of 8.82 μM. While the inhibition of CYP2C9 and 2E1 was competitive with the K_i values of 5.54 and 7.79 μM, respectively. After incubating for 0, 5, 10, 15, and 30 min, the inhibition of CYP3A4 was revealed to be time-dependent with the K_I value of 4.87 μM^− 1 and the K_inact value of 0.0515 min^− 1.

Conclusions

The in vitro inhibitory effect of obtusofolin implying the potential drug-drug interaction between obtusofolin and corresponding substrates, which needs further in vivo validations.