LC-MS determination and pharmacokinetic studies of paeonol in rat plasma after administration of different compatibility of Su-Xiao-Xin-Tong prescriptions

Pharmacokinetics, Tissue Distribution and Excretion of Paeonol and Its Major Metabolites in Rats Provide a Further Insight Into Paeonol Effectiveness

Paeonol is a major bioactive ingredient in Moutan Cortex (the root barks of Paeonia suffruticosa Andrews) and exhibited a wide range of bioactivities such as anti-inflammation, anti-oxidation, hypoglycemic effect, analgesic, and others. Even though paeonol has been proven to possess significant pharmacological and therapeutic effects, its pharmacokinetic properties are not satisfactory since it has been found to have a rapid clearance in vivo. In the present study, the pharmacokinetics, tissue distribution and excretion of paeonol and its major metabolites were investigated in rats by an efficient and specific UPLC-MS/MS method. The results indicated that paeonol was rapidly absorbed, extensively metabolized, and widely distributed in various tissues without long-term accumulation after oral administration to rats. The major distribution tissues of paeonol and its metabolites were kidney, liver, and heart. Paeonol was able to cross the blood-brain barrier but rapidly decreased after 10 min. The total excretion of four metabolites in urine, bile, and feces was approximately 35.0% within 24 h, and the metabolites were mainly excreted through the urine. In addition, the hypoglycemic activities of paeonol and its metabolites were investigated by a glucose uptake assay on TNF-α mediated insulin resistance in 3T3-L1 adipocytes. The results showed that paeonol and its major metabolites displayed hypoglycemic activities. This is the first comprehensive and systematic report on the pharmacokinetics of paeonol and its metabolites. This research provides an important basis for the clinical development and application of active metabolites.

Pharmacokinetics and Brain Distribution of the Active Components of DA-9805, Saikosaponin A, Paeonol, and Imperatorin in Rats

DA-9805 is a botanical anti-Parkinson’s drug candidate formulated from ethanol extracts of the root of Bupleurum falcatum, the root cortex of Paeonia suffruticosa, and the root of Angelica dahurica. The pharmacokinetics (PKs) and brain distribution of active/representative ingredients of DA-9805, Saikosaponin a (SSa; 1.1–4.6 mg/kg), Paeonol (PA; 14.8–59.2 mg/kg), and Imperatorin (IMP; 1.4–11.5 mg/kg) were evaluated following the intravenous or oral administration of each pure component and the equivalent dose of DA-9805 in rats. All three components had greater dose-normalized areas under the plasma concentration-time curve (AUC) and slower clearance with higher doses, following intravenous administration. By contrast, dose-proportional AUC values of SSa, PA, and IMP were observed following the oral administration of each pure component (with the exception of IMP at the highest dose) or DA-9805. Compared to oral administration of each pure compound, DA-9805 administration showed an increase in the AUC of SSa (by 96.1–163%) and PA (by 155–164%), possibly due to inhibition of their metabolism by IMP or other component(s) in DA-9805. A delay in the absorption of PA and IMP was observed when they were administered as DA-9805. All three components of DA-9805 showed greater binding values in brain homogenates than in plasma, possibly explaining why the brain-to-plasma ratios were greater than unity following multiple oral administrations of DA-9805. By contrast, their levels in cerebrospinal fluid were negligible. Our results further our understanding of the comprehensive PK characteristics of SSa, PA, and IMP in rats and the comparative PKs between each pure component and DA-9805.

LC/MS/MS determination and pharmacokinetic studies of six compounds in rat plasma following oral administration of the single and combined extracts of Eucommia ulmoides and Dipsacus asperoides

AIM

To establish and apply a new LC/MS/MS method for the simultaneous, quantitative determination of six ingredients, aucubin (AU), geniposide (GP), geniposidic acid (GPA), pinoresinol diglucoside (PDG), secologanin (SLG), and loganin (LG) in single and combined extracts of Eucommia ulmoides and Dipsacus asperoides.

METHOD

Using the LC/MS/MS-ESI(-)-MRM mode to detect the six compounds, chromatographic separation was achieved on an Agilent Eclipse plus C18 column, and the mobile phase consisted of solvent A (CH3CN) and solvent B (H2O containing 0.01% CH3COOH V/V).

RESULTS

This method was successfully applied to quantify the six compounds in rat plasma after oral administration, and showed good precision, accuracy, reproducibility, and linear regression (r(2)>0.99).

CONCLUSION

The results showed that following the use of the two medicinal plants, for AU and GP, the values of Cmax markedly increased, and the values of cmax markedly decreased. It was found that the compatibility of the medicinal plants might affect their pharmacokinetic properties of their constituents.

Low-dose paeonol derivatives alleviate lipid accumulation

Here, we present a series of novel paeonol derivatives that prevent lipid accumulation at lower doses.

Novel effect of paeonol on the formation of foam cells: promotion of LXRα-ABCA1-dependent cholesterol efflux in macrophages

Paeonol, a phenolic component purified from Paeonia suffruticosa (Cortex Moutan), is used in traditional Chinese medicine to treat inflammatory diseases. However, little is known about the effect of paeonol on cholesterol metabolism. We investigated the efficacy of paeonol on cholesterol metabolism and the underlying mechanism in macrophages and apolipoprotein E deficient (apoE(-/-)) mice. Treatment with paeonol markedly attenuated cholesterol accumulation induced by oxidized LDL in macrophages, which was due to increased cholesterol efflux. Additionally, paeonol enhanced the mRNA and protein expression of ATP-binding membrane cassette transport protein A1 (ABCA1) but did not alter the protein level of ABCG1 or other scavenger receptors. Inhibition of ABCA1 activity with a pharmacological inhibitor, neutralizing antibody or small interfering RNA (siRNA), negated the effects of paeonol on cholesterol efflux and cholesterol accumulation. Furthermore, paeonol induced the nuclear translocation of liver X receptor α (LXRα) by increasing its activity. siRNA knockdown of LXRα abolished the paeonol-induced upregulation of ABCA1, promotion of cholesterol efflux and suppression of cholesterol accumulation. Moreover, atherosclerotic lesions, hyperlipidemia and systemic inflammation were reduced and the protein expression of ABCA1 was increased in aortas of paeonol-treated apoE(-/-) mice. Paeonol may alleviate the formation of foam cells by enhancing LXRα-ABCA1-dependent cholesterol efflux.

Electrochemical oxidation and detection of paeonol on modified electrode with acetylene black nanoparticles

With an aim to construct a sensing platform for the electrochemical detection of paeonol, we modified the glassy carbon electrode with acetylene black nanoparticle (AB). A sensitive oxidation peak of paeonol was observed with remarkably increased peak current on the modified electrode because the electrode has a big surface area due to three dimensional structure of AB nanoparticles. The optimization of detection conditions was performed, including pH value of the buffer, the amount of AB nanoparticles on the electrode surface, the accumulation potential and time of paeonol. Under the optimized conditions, the oxidation peak current of paeonol increased linearly with its concentration over the range from 5×10(-7) to 1×10(-4) M. The detection limit was calculated to be 1×10(-7) M. The modified electrode was successfully applied to detect the content of paeonol in cortex moutan, a common traditional Chinese medicine. The method is new, sensitive, rapid and convenient for the detection of paeonol.

Traditional Chinese medicine and separation science

Traditional Chinese medicines (TCMs) are getting more and more popular nowadays in the whole world for improving health condition of human beings as well as preventing and healing diseases. TCM is a multi-component system with components mostly unknown, and only a few compounds are responsible for the pharmaceutical and/or toxic effects. The large numbers of other components in the TCM make the screening and analysis of the bioactive components extremely difficult. So, separation and analysis of the desired chemical components in TCM are very important subjects for modernization research of TCM. Thus, many novel separation techniques with significant advantages over conventional methods were introduced and applied to separation and analysis of the chemical constituents in TCM. This review presents just a brief outline of the applications of different separation methods for the isolation and analysis of TCM constituents.