Bazhu Decoction, a Traditional Chinese Medical Formula, Ameliorates Cognitive Deficits in the 5xFAD Mouse Model of Alzheimer's Disease.

Alzheimer's disease (AD) is the most common neurodegenerative disorder associated with aging. There are currently no effective treatments for AD. Bazhu decoction (BZD), a traditional Chinese medicine (TCM) formula, has been employed clinically to alleviate AD. However, the underlying molecular mechanisms are still unclear. Here we found that middle- and high-doses of BZD ameliorated the behavioral aspects of 5xFAD transgenic mice in elevated plus maze, Y maze and Morris water maze tests. Moreover, BZD reduced the protein levels of BACE1 and PS1, resulting in a reduction of Aß plaques. We also identified a beneficial effect of BZD on oxidative stress by attenuating MDA levels and SOD activity in the brains of 5xFAD mice. Together, these results indicate that BZD produces a dose-dependent positive effect on 5xFAD transgenic mouse model by decreasing APP processing and Aß plaques, and by ameliorating oxidative damage. BZD may play a protective role in the cognitive and anxiety impairments and may be a complementary therapeutic option for AD.

Prediction of Drug-Drug Interaction between Tacrolimus and Principal Ingredients of Wuzhi Capsule in Chinese Healthy Volunteers Using Physiologically-Based Pharmacokinetic Modelling.

Schisantherin A and schisandrin A, the most abundant active ingredients of Wuzhi capsule, are known to inhibit tacrolimus metabolism by inhibiting CYP3A4/5. We aimed to predict the contribution of schisantherin A and schisandrin A to drug-drug interaction (DDI) between Wuzhi capsule and tacrolimus using physiologically-based pharmacokinetic (PBPK) modelling. Firstly, the inhibition mechanism of schisantherin A and schisandrin A on CYP3A4/5 was investigated. Thereafter, PBPK models of schisantherin A, schisandrin A and tacrolimus were established. Finally, tacrolimus pharmacokinetics were evaluated after the combined use with schisantherin A or schisandrin A. The blood area under the curve (AUC) of tacrolimus increased 1.77- and 2.61-fold after a single dose and multiple doses of schisantherin A, respectively. Meanwhile, schisandrin A inhibited tacrolimus metabolism to a smaller extent. Also, it showed that mechanism-based inhibition (MBI) played a more important role in DDI than reversible inhibition after long-term administration, while reversible inhibition was comparable to MBI after single-dose administration. In conclusion, we utilized PBPK modelling to quantify the contribution of schisantherin A and schisandrin A to DDI between tacrolimus and Wuzhi capsule. This may provide more insights for the rational use of this drug combination.

Identification of human cytochrome P450 and UGT enzymes involved in the metabolism of ferulic acid, a major bioactive component in traditional Chinese medicines.

Ferulic acid (FA) is an active component of herbal medicines. One of the best documented activities of FA is its antioxidant property. Moreover, FA exerts antiallergic, anti-inflammatory, and hepatoprotective effects. However, the metabolic pathways of FA in humans remain unclear. To identify whether human CYP or UGT enzymes are involved in the metabolism of FA, reaction phenotyping of FA was conducted using major CYP-selective chemical inhibitors together with individual CYP and UGT Supersomes. The CYP- and/or UGT-mediated metabolism kinetics were examined simultaneously or individually. Relative activity factor and total normalized rate approaches were used to assess the relative contributions of each major human CYPs towards the FA metabolism. Incubations of FA with human liver microsomes (HLM) displayed NADPH- and UDPGA-dependent metabolism with multiple CYP and UGT isoforms involved. CYPs and UGTs contributed equally to the metabolism of FA in HLM. Although CYP1A2 and CYP3A4 appeared to be the major contributors in the CYP-mediated clearance, their contributions to the overall clearance are still minor (< 25%). As a constitute of many food and herbs, FA poses low drug-drug interaction risk when co-administrated with other herbs or conventional medicines because multiple phase I and phase II enzymes are involved in its metabolism.

Separation and simultaneous quantification of nine furanocoumarins from Radix Angelicae dahuricae using liquid chromatography with tandem mass spectrometry for bioavailability determination in rats.

Radix Angelicae dahuricae is a well-known medicinal herb in a number of herb preparations for medical uses. In this study, a rapid and selective method using liquid chromatography with tandem mass spectrometry was developed for the separation and simultaneous quantitation of nine furanocoumarins from Radix A. dahuricae, namely imperatorin, isoimperatorin, oxypeucedanin hydrate, bergapten, oxypeucedanin, xanthotoxol, xanthotoxin, isopimpinellin, and psoralen. Chromatographic separation was achieved on a CAPCELL PAK MG II C18 analytical column. Detection was performed using positive electrospray ion source in the multiple reaction monitoring mode. The method was fully validated for analyzing these principles in rat plasma with a lower limit of quantification from 0.5 to 5 ng/mL. The intra- and interbatch precisions were less than 10%, and the accuracies ranged from -7.5 to 8.0%. The extraction recovery of the analytes was above 70% without a significant matrix effect. The method was used to determine the oral and intravenous pharmacokinetic profiles of these furanocoumarins after dosing with Radix A. dahurica extract. The bioavailability of these furanocoumarins ranged from 10.1 to 82.8%. These data provide critical information for a better understanding of the pharmacological mechanisms and herb-drug interaction potential of Radix A. dahurica.

Characterization of preclinical in vitro and in vivo ADME properties and prediction of human PK using a physiologically based pharmacokinetic model for YQA-14, a new dopamine D3 receptor antagonist candidate for treatment of drug addiction.

YQA-14 is a novel and selective dopamine D3 receptor antagonist, with potential for the treatment of drug addiction. However, earlier compounds in its structural class tend to have poor oral bioavailability. The objectives of this study were to characterize the preclinical absorption, distribution, metabolism and excretion (ADME) properties and pharmacokinetics (PK) of YQA-14, then to simulate the clinical PK of YQA-14 using a physiologically based pharmacokinetics (PBPK) model to assess the likelihood of developing YQA-14 as a clinical candidate. For human PK prediction, PBPK models were first built in preclinical species, rats and dogs, for validation purposes. The model was then modified by input of human in vitro ADME data obtained from in vitro studies. The study data showed that YQA-14 is a basic lipophilic compound, with rapid absorption (Tmax ~ 1 h) in both rats and dogs. Liver microsomal clearances and in vivo clearances were moderate in rats and dogs consistent with the moderate bioavailability observed in both species. The PBPK models built for rats and dogs simulated the observed PK data well in both species. The PBPK model refined with human data predicted that YQA-14 would have a clearance of 8.0 ml/min/kg, a volume distribution of 1.7 l/kg and a bioavailability of 16.9%. These acceptable PK properties make YQA-14 an improved candidate for further research and development as a potential dopamine D3R antagonism for the treatment of drug addiction in the clinic.

Simultaneous determination of triptolide and its prodrug MC002 in dog blood by LC-MS/MS and its application in pharmacokinetic studies.

ETHNOPHARMACOLOGICAL RELEVANCE: Tripterygium wilfordii HOOK F (TWHF) is a traditional Chinese medicine used in the treatment of various autoimmune diseases and inflammatory disorders including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and skin diseases. Triptolide (TP) is one of the main active ingredients of this traditional Chinese medicine. MC002 is a novel semi-synthetic derivate of TP which is highly water soluble, acts as a prodrug and is converted to TP in vivo. AIM OF THIS STUDY: A sensitive, rapid method for the simultaneous determination of TP and its chemo-unstable prodrug MC002 in dog blood was developed and validated using electrospray ionization (ESI) liquid chromatography-tandem mass spectrometry (LC-MS/MS). Using this method, a pharmacokinetic study of MC002 and TP following an intravenous drip infusion of 0.2mg/kg MC002 in dogs was performed. MATERIALS AND METHODS: Chemo-degradation of the prodrug in blood samples was inhibited by the addition of a small amount of sodium fluoride solution before using liquid-liquid extraction with ethyl acetate. The concentrations of MC002 and TP in dog blood were determined using the LC-MS/MS method. RESULTS: The quantitative method showed good precision and stability and is suitable for the assay of biological samples. The pharmacokinetic study showed that the elimination of MC002 was faster than that of TP, and the concentrations and AUC0-t values of TP were higher than MC002. MC002 can rapidly convert to TP in vivo. CONCLUSIONS: This validated method was successfully applied in a pharmacokinetic study of MC002 following an intravenous drip infusion in dogs. With the development of this new prodrug of TP as a promising anti-cancer drug, this method is suitable for its further analysis in clinical studies.

Identification and characterization of psoralen and isopsoralen as potent CYP1A2 reversible and time-dependent inhibitors in human and rat preclinical studies.

Naturally occurring furanocoumarin compounds psoralen (PRN) and isopsoralen (IPRN) are bioactive constituents found in herbaceous plants. They are widely used as active ingredients in several Chinese herbal medicines. In this study, the CYP1A2 inhibitory potential of PRN and IPRN was investigated in rats in vitro and in vivo as well as in human liver microsomes. Both compounds exhibited reversible and time-dependent inhibition toward rat microsomal cyp1a2. The IC(50), k(inact), and K(I) values were 10.4 ± 1.4 µM, 0.060 ± 0.002 min(-1), and 1.13 ± 0.12 µM for PRN, and 7.1 ± 0.6 µM, 0.10 ± 0.01 min(-1), and 1.95 ± 0.31 µM for IPRN, respectively. In human liver microsomal incubations, potent reversible CYP1A2 inhibition was observed for both compounds, with IC(50) values of 0.26 ± 0.01 µM and 0.22 ± 0.03 µM for PRN and IPRN, respectively. However, time-dependent inhibition was only observed for IPRN, with kinact and KI values of 0.050 ± 0.002 min(-1) and 0.40 ± 0.06 µM, respectively. Coadministration with PRN or IPRN significantly inhibited cyp1a2 activity in rats, with the area under the curve (AUC) of phenacetin increasing more than 5-fold. Simcyp simulation predicted that PRN would cause 1.71- and 2.12-fold increases in the phenacetin AUC in healthy volunteers and smokers, respectively. IPRN, on the other hand, would result in 3.24- and 5.01-fold increases in phenacetin AUCs in healthy volunteers and smokers, respectively. These findings represent the first detailed report comparing the potential drug-drug interactions of PRN and IPRN, and provide useful information for balancing safe and efficacious doses of PRN and IPRN.

Pre-column derivatization combined with UHPLC-MS/MS for rapid and sensitive quantification of bakuchiol in rat plasma.

Psoralea corylifolia L. (Fabaceae) is a traditional Chinese medicine with many beneficial effects in medical therapies. Bakuchiol was the main active ingredient of Psoralea corylifolia L. In this study, a novel method of pre-column derivatization with dansyl chloride followed by analysis of ultra high-performance liquid chromatographic-tandem mass spectrometry (UHPLC-MS/MS) was established and validated for quantification of bakuchiol in rat plasma. The linearity of this approach was confirmed to be within the concentration range of 0.5-1000 ng/mL and the lower limit of quantification was at 0.5 ng/mL. The total analysis time was 1.5 min for each pretreated sample. Also, the precision, accuracy, stability, recovery and matrix effect of this method were proved to meet the requirements for bioanalysis. The intravenous and oral pharmacokinetic profiles of bakuchiol were obtained by utilizing this approach. The oral bioavailability of bakuchiol in rats (3.2%) was identified.

Development and preclinical studies of broad-spectrum anti-HIV agent (3'R,4'R)-3-cyanomethyl-4-methyl-3',4'-di-O-(S)-camphanoyl-(+)-cis-khellactone (3-cyanomethyl-4-methyl-DCK).

In prior investigation, we discovered that (3'R,4'R)-3-cyanomethyl-4-methyl-3',4'-di-O-(S)-camphanoyl-(+)-cis-khellactone (4, 3-cyanomethyl-4-methyl-DCK) showed promising anti-HIV activity. In these current studies, we developed and optimized successfully a practical 10-step synthesis for scale-up preparation to increase the overall yield of 4 from 7.8% to 32%. Furthermore, compound 4 exhibited broad-spectrum anti-HIV activity against wild-type and drug-resistant viral infection of CD4+ T cell lines as well as peripheral blood mononuclear cells by both laboratory-adapted and primary HIV-1 isolates with distinct subtypes and tropisms. Compound 4 was further subjected to in vitro and in vivo pharmacokinetic studies. These studies indicated that 4 has moderate cell permeability, moderate oral bioavailability, and low systemic clearance. These results suggest that 4 should be developed as a promising anti-HIV agent for development as a clinical trial candidate.