Synthesis of fluorescent Molecularly Imprinted Polymer Nanoparticles Sensing Small Neurotransmitters with High Selectivity Using Immobilized Templates with Regulated Surface Density

To develop nanosensors to probe neurotransmitters, we synthesized fluorescent-functionalized molecularly imprinted polymeric nanoparticles (fMIP-NPs) using monoamine neurotransmitters (serotonin and dopamine) immobilized on glass beads as templates. The size and fluorescence intensity of the fMIP-NPs synthesized with blended silane couplers increased with the presence of the target but were insensitive to the target analogs (L-tryptophan and L-dopa, respectively). However, when the template is anchored by a pure silane agent, both the fluorescence intensity and particle size of the fMIP-NPs were sensitive to the structural analog of the template. Another fMIP-NP was synthesized in the presence of poly([2-(methacryloyloxy)ethyl] trimethylammonium chloride (METMAC)-co-methacrylamide) grafted onto glass beads as a dummy template for acetylcholine. Acetylcholine increased the diameter and fluorescence intensity of the fMIP-NP, but choline had no effect. When the homopolymer of METMAC was used as a template, the fluorescence intensity and size of the resulting nanoparticles were not responsive to either acetylcholine or choline. The principle of increased fluorescence intensity due to specific interaction with the target substance is probably due to the increased distance between the fluorescent functional groups and decreased self-quenching due to the swelling caused by the specific interaction with the template. The results also indicate that MIP nanoparticles prepared by solid-phase synthesis can be used for targeting small molecules, such as the neurotransmitters addressed in this study, by adjusting the surface density of the template.

Targeting intestinal flora and its metabolism to explore the laxative effects of rhubarb

Rhubarb, a traditional herb, has been used in clinical practice for hundreds of years to cure constipation, but its mechanism is still not clear enough. Currently, growing evidence suggests that intestinal flora might be a potential target for the treatment of constipation. Thus, the aim of this study was to clarify the laxative effect of rhubarb via systematically analyzing the metagenome and metabolome of the gut microbiota. In this study, the laxative effects of rhubarb were investigated by loperamide-induced constipation in rats. The gut microbiota was determined by high-throughput sequencing of 16S rRNA gene. Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry was used for fecal metabolomics analysis. The data showed that rhubarb could significantly shorten gastrointestinal transit time, increase fecal water content and defecation frequency, improve gastrointestinal hormone disruption, and protect the colon mucus layer. Analysis of 16S rRNA gene sequencing indicated that rhubarb could improve the disorder of intestinal microbiota in constipated rats. For example, beneficial bacteria such as Ligilactobacillus, Limosilalactobacillus, and Prevotellaceae UCG-001 were remarkably increased, and pathogens such as Escherichia-Shigella were significantly decreased after rhubarb treatment. Additionally, the fecal metabolic profiles of constipated rats were improved by rhubarb. After rhubarb treatment, metabolites such as chenodeoxycholic acid, cholic acid, prostaglandin F2α, and α-linolenic acid were markedly increased in constipation rats; in contrast, the metabolites such as lithocholic acid, calcidiol, and 10-hydroxystearic acid were notably reduced in constipation rats. Moreover, correlation analysis indicated a close relationship between intestinal flora, fecal metabolites, and biochemical indices associated with constipation. In conclusion, the amelioration of rhubarb in constipation might modulate the intestinal microflora and its metabolism. Moreover, the application of fecal metabolomics could provide a new strategy to uncover the mechanism of herbal medicines.Key points• Rhubarb could significantly improve gut microbiota disorder in constipation rats.• Rhubarb could markedly modulate the fecal metabolite profile of constipated rats.

Pharmacokinetics and Pharmacodynamics of Huanglian-Houpo Decoction Based on Berberine Hydrochloride and Magnolol Against H1N1 Influenza Virus

BACKGROUND AND OBJECTIVES

Huanglian-Houpo decoction (HH), which is recorded in the famous traditional Chinese medicine monograph "Puji Fang," contains two individual herbs, Huanglian (Rhizoma coptidis) and Houpo (Magnoliae officinalis cortex). It was regularly used to treat seasonal epidemic colds and influenzas in ancient China. Our laboratory discovered that HH has a significant anti-H1N1 influenza virus effect. However, no pharmacokinetic and pharmacodynamic data concerning the anti-H1N1 influenza virus activity of HH are available to date. In the current study, the concentration-time profiles of two major components of HH, berberine and magnolol, in rat plasma were investigated.

METHODS

An integrate pharmacokinetic approach was developed for evaluating the holistic pharmacokinetic characteristics of berberine and magnolol from HH. Additionally, the inhibition rate and levels of IFN-β in MDCK cells infected by influenza virus were analyzed. Data were calculated using 3p97 with pharmacokinetic analysis.

RESULTS

The estimated pharmacokinetic parameters were maximum plasma concentration (C_max) 0.9086 μg/ml, area under the concentration-time curve (AUC) 347.74 μg·min/ml, and time to reach C_max (T_max) 64.69 min for berberine and C_max = 0.9843 μg/ml, AUC= 450.64 μg·min/ml, T_max = 56.86 min for magnolol, respectively. Furthermore, integrated pharmacokinetic and pharmacodynamic analysis showed that the highest plasma concentration, inhibition rate and interferon-β (IFN-β) secretion of HH first increased and then weakened over time, reaching their peaks at 60 min. The plasma concentration of HH is directly related to the anti-influenza virus effect.

CONCLUSION

The results indicated that berberine and magnolol are the main active ingredients of HH related to its anti-influenza virus effect, which is related to the improvement of IFN-β secretion.

Association Between N-Desmethylclozapine and Clozapine-Induced Sialorrhea: Involvement of Increased Nocturnal Salivary Secretion via Muscarinic Receptors by N-Desmethylclozapine

Clozapine-induced sialorrhea (CIS) is a common side effect of clozapine. There is no established standard treatment of CIS since the underlying mechanism remains unknown. This study aimed to elucidate the mechanisms involved in CIS. In our clinical study, a prospective observational study evaluated the association between serum and saliva concentrations of clozapine or its metabolites and Drooling Severity and Frequency Scale (DSFS) score. In our in vivo study, we first developed a new CIS animal model; subsequently, we measured salivary secretion and concentrations of clozapine or its metabolites in the animal model. In our in vitro study, we measured the calcium ion (Ca²⁺) response to evaluate the effect of clozapine or its metabolites on human salivary gland cell line (HSY cells) and then examined whether their effect was inhibited by atropine. In our clinical study, serum and saliva N-desmethylclozapine concentrations were significantly correlated with nocturnal DSFS score. In our in vivo study, daily single oral administration of 100 mg/kg clozapine for 7 days significantly increased salivary secretion in rats. Furthermore, N-desmethylclozapine concentrations in serum and submandibular glands of the rats were higher than clozapine concentrations. In our in vitro study, N-desmethylclozapine only elicited an increase in the intracellular Ca²⁺ in HSY cells. N-desmethylclozapine-induced Ca²⁺ responses were inhibited by atropine. These results suggest that N-desmethylclozapine is implicated in CIS by increasing nocturnal salivation via the muscarinic receptors. Moreover, our developed animal model that reflects CIS in clinical condition plays a key role as a bridge between basic and clinical research. SIGNIFICANCE STATEMENT: Clozapine-induced sialorrhea (CIS) is a severe and frequent adverse reaction, but the mechanism underlying CIS is less well understood. This paper reports that N-desmethylclozapine, a metabolite of clozapine, is implicated in CIS by increasing nocturnal salivation via the muscarinic receptors and that oral administration of clozapine at 100 mg/kg once daily for 7 days to rat is the optimum method for establishing the new animal model reflecting the clinical scenario of CIS.

Cellular Uptake of the Atypical Antipsychotic Clozapine Is a Carrier-Mediated Process

The weak base antipsychotic clozapine is the most effective medication for treating refractory schizophrenia. The brain-to-plasma concentration of unbound clozapine is greater than unity, indicating transporter-mediated uptake, which has been insufficiently studied. This is important, because it could have a significant impact on clozapine's efficacy, drug-drug interaction, and safety profile. A major limitation of clozapine's use is the risk of clozapine-induced agranulocytosis/granulocytopenia (CIAG), which is a rare but severe hematological adverse drug reaction. We first studied the uptake of clozapine into human brain endothelial cells (hCMEC/D3). Clozapine uptake into cells was consistent with a carrier-mediated process, which was time-dependent and saturable ( V_max = 3299 pmol/million cells/min, K_m = 35.9 μM). The chemical inhibitors lamotrigine, quetiapine, olanzapine, prazosin, verapamil, indatraline, and chlorpromazine reduced the uptake of clozapine by up to 95%. This could in part explain the in vivo interactions observed in rodents or humans for these compounds. An extensive set of studies utilizing transporter-overexpressing cell lines and siRNA-mediated transporter knockdown in hCMEC/D3 cells showed that clozapine was not a substrate of OCT1 (SLC22A1), OCT3 (SLC22A3), OCTN1 (SLC22A4), OCTN2 (SLC22A5), ENT1 (SLC29A1), ENT2 (SLC29A2), and ENT4/PMAT (SLC29A4). In a recent genome-wide analysis, the hepatic uptake transporters SLCO1B1 (OATP1B1) and SLCO1B3 (OATP1B3) were identified as additional candidate transporters. We therefore also investigated clozapine transport into OATP1B-transfected cells and found that clozapine was neither a substrate nor an inhibitor of OATP1B1 and OATP1B3. In summary, we have identified a carrier-mediated process for clozapine uptake into brain, which may be partly responsible for clozapine's high unbound accumulation in the brain and its drug-drug interaction profile. Cellular clozapine uptake is independent from currently known drug transporters, and thus, molecular identification of the clozapine transporter will help to understand clozapine's efficacy and safety profile.

Pharmacokinetics of Chinese medicines: strategies and perspectives

The modernization and internationalization of Chinese medicines (CMs) are hampered by increasing concerns on the safety and the efficacy. Pharmacokinetic (PK) study is indispensable to establish concentration-activity/toxicity relationship and facilitate target identification and new drug discovery from CMs. To cope with tremendous challenges rooted from chemical complexity of CMs, the classic PK strategies have evolved rapidly from PK study focusing on marker/main drug components to PK-PD correlation study adopting metabolomics approaches to characterize associations between disposition of global drug-related components and host metabolic network shifts. However, the majority of PK studies of CMs have adopted the approaches tailored for western medicines and focused on the systemic exposures of drug-related components, most of which were found to be too low to account for the holistic benefits of CMs. With an area under concentration-time curve- or activity-weighted approach, integral PK attempts to understand the PK-PD relevance with the integrated PK profile of multiple co-existing structural analogs (prototyes/metabolites). Cellular PK-PD complements traditional PK-PD when drug targets localize inside the cells, instead of at the surface of cell membrane or extracellular space. Considering the validated clinical benefits of CMs, reverse pharmacology-based reverse PK strategy was proposed to facilitate target identification and new drug discovery. Recently, gut microbiota have demonstrated multifaceted roles in drug efficacy/toxicity. In traditional oral intake, the presystemic interactions of CMs with gut microbiota seem inevitable, which can contribute to the holistic benefits of CMs through biotransforming CMs components, acting as the peripheral target, and regulating host drug disposition. Hence, we propose a global PK-PD approach which includes the presystemic interaction of CMs with gut microbiota and combines omics with physiologically based pharmacokinetic modeling to offer a comprehensive understanding of the PK-PD relationship of CMs. Moreover, validated clinical benefits of CMs and poor translational potential of animal PK data urge more research efforts in human PK study.

Recent advances in pharmacokinetics approach for herbal medicine

Traditional Chinese Medicine (TCM), an indispensable part of herbal medicine, has been used for treating many diseases and/or symptoms for thousands of years.

Pharmacokinetic interactions of herbal medicines for the treatment of chronic hepatitis

Chronic liver disease is a serious global health problem, and an increasing number of patients are seeking alternative medicines or complementary treatment. Herbal medicines account for 16.8% of patients with chronic liver disease who use complementary and alternative therapies. A survey of the National Health Insurance Research Database in Taiwan reported that Long-Dan-Xie-Gan-Tang, Jia-Wei-Xia-Yao-San, and Xiao-Chai-Hu-Tang (Sho-saiko-to) were the most frequent formula prescriptions for chronic hepatitis used by traditional Chinese medicine physicians. Bioanalytical methods of herbal medicines for the treatment of chronic hepatitis were developed to investigate pharmacokinetics properties, but multicomponent herbal formulas have been seldom discussed. The pharmacokinetics of herbal formulas is closely related to efficacy, efficiency, and patient safety of traditional herbal medicines. Potential herbal formula–drug interactions are another essential issue during herbal formula administration in chronic hepatitis patients. In a survey with the PubMed database, this review article evaluates the existing evidence-based data associated with the documented pharmacokinetics profiles and potential herbal–drug interactions of herbal formulas for the treatment of chronic hepatitis. In addition, the existing pharmacokinetic profiles were further linked with clinical practice to provide insight for the safety and specific use of traditional herbal medicines.