LC Tissue Distribution Study of Paeonol in Rats after Oral Administration

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.

Investigation on the Preparation, Characteristics, and Controlled Release Model of Paeonol-Loaded Liposome in Carbomer Hydrogel

OBJECTIVE

Paeonol is a phenolic compounce that is volatile. In order to decrease its volatility and achieve controlled release, paeonol-loaded liposome in carbomer hydrogel was prepared by coating with soybean phospholipid via ethanol injection method and then added into the carbomer hydrogel.

METHODS

The quality of paeonol-loaded liposome in carbomer hydrogel was evaluated by the degree of roundness, particle size distribution, zeta potential, entrapment efficiency (filtration method and chitosan neutralization method), viscosity, infrared spectrum, etc. Furthermore, the diffusion from paeonolloaded liposome in hydrogel was studied in vitro.

RESULTS

The results showed that the average particle size of paeonol-loaded liposome was about 401 nm, the potential was -17.8 mV, and the entrapment efficiency was above 45%. The viscosity of paeonol- loaded liposome in hydrogel was 23.972×10-3 Pa*s, and the diffusion rate from paeonol-loaded liposome in hydrogel in vitro was obviously slower than that from the other paeonol preparations.

CONCLUSION

The conclusions could be drawn that paeonol-loaded liposome in hydrogel was a kind of novel preparation, and its diffusion in vitro had obvious controlled-release characteristics, which further proved that it might improve the bioavailability of paeonol.

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.

Paeonolum protects against MPP(+)-induced neurotoxicity in zebrafish and PC12 cells

Background

Parkinson’s disease (PD) is the second most common neurodegenerative disease, affecting 2% of the population aged over 65 years old. Mitochondrial defects and oxidative stress actively participate in degeneration of dopaminergic (DA) neurons in PD. Paeonolum, a main component isolated from Moutan cortex, has potent antioxidant ability. Here, we have examined the effects of paeonolum against MPP⁺-induced neurotoxicity in zebrafish and PC12 cells.

Methods

The overall viability and neurodegeneration of DA neurons was assessed in ETvmat2:green fluorescent protein (GFP) transgenic zebrafish, in which most monoaminergic neurons are labeled by GFP. Damage to PC12 cells was measured using a cell viability assay and assessment of nuclear morphology. Intracellular reactive oxygen species (ROS) and the level of total GSH were assessed. The mitochondrial cell death pathway including mitochondrial membrane potential, cytochrome C release and caspase-3 activity were also examined in PC12 cells.

Results

Paeonolum protected against MPP⁺-induced DA neurodegeneration and locomotor dysfunction in zebrafish in a concentration-dependent manner. Similar neuroprotection was replicated in the PC12 cellular model of MPP⁺ toxicity. Paeonolum attenuated MPP⁺-induced intracellular ROS accumulation and restored the level of total GSH in PC12 cells. Furthermore, paeonolum significantly inhibited the mitochondrial cell death pathway induced by MPP⁺.

Conclusions

Collectively, the present study demonstrates that paeonolum protects zebrafish and PC12 cells against MPP⁺-induced neurotoxicity.

Metabolism and tissue distribution study of Vaccaria seeds (Wang-Bu-Liu-Xing) in benign prostatic hyperplasia model rat: toward an in-depth study for its bioactive components

Vaccaria seeds (Wang-Bu-Liu-Xing), a well-known traditional Chinese medicine (TCM), has been used as an emperor herb of many ancient formulas to treat benign prostatic hyperplasia (BPH) in clinic. However, its metabolism and tissue distribution, especially in the target tissue, had not been investigated so far. Based on the hypothesis that the components which exert effect against BPH of Vaccaria seeds would be measureable in target tissue (prostate), in vivo metabolism and tissue distribution of Vaccaria seeds in rats were profiled using a specific and sensitive high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (LC-QTOF-MS/MS). As a result, 19 major constituents in the Vaccaria seeds decoction and 19 constituents in rat plasma, feces and tissues after oral administration of Vaccaria seeds decoction were identified. Accurate mass measurement for molecular ions and characteristic fragment ions could represent reliable identification criteria for these compounds. Two prototypes were detected in prostate. An in vitro metabolism analysis of them was studied after incubation with rat intestinal flora and rat liver microsome (RLM) in this paper, which is helpful for further investigation of the potential effect of these two components. The result of this study provided meaningful information for further pharmacology research on Vaccaria seeds.