Pyrrolizidine alkaloids in tea, herbal tea and iced tea beverages- survey and transfer rates.

The transfer rate of 37 pyrrolizidine alkaloids (PA) found in ten naturally contaminated teas and herbal teas to their brews was studied in detail. Mixed herbal, peppermint, red bush, senna, black tea and green tea infusions were prepared according to the ISO guide and vendor's instructions, respectively, and parameters like herb-to-water ratio, steeping time and multiple extractions studied. In general, a transfer rate of 38-100% (median 95%) for brews following vendor's instructions was determined. The total concentration range of PA in these ten samples was 154-2412 ng/g (median 422 ng/g) in the herb and for single analytes 0.1-170 ng/g. Seven of the 37 PA occurred unexpectedly; these were tentatively identified and quantified by liquid chromatography-high resolution mass spectrometry (LC-HR-MS), since their contributions to total PA-content matter. Additionally, 46 iced tea beverages were analysed for their PA-load, determined to be in the range 0-631 ng/L (median 40 ng/L). The applied solid-phase extraction (SPE) clean-up turned out to be capable of separating PA in the free base pyrrolizidine alkaloids (PAFB) and their N-oxides (PANO) in a two-step elution, which was a valuable tool to support identification of unexpected PA. Further, atropine was found in 50% of the ten tea herb samples (range: 1-4 ng/g) and in 13% of the iced tea beverage samples (range: 2-65 ng/L).

New developments in optimizing bronchodilator treatment of COPD: a focus on glycopyrrolate/formoterol combination formulated by co-suspension delivery technology.

COPD causes considerable health and economic burden worldwide, with incidence of the disease expected to continue to rise. Inhaled bronchodilators, such as long-acting muscarinic antagonists (LAMAs) and long-acting ß2-agonists (LABAs), are central to the maintenance treatment of patients with COPD. Clinical studies have demonstrated that combined LAMA + LABA therapies improve efficacy while retaining a safety profile similar to LAMA or LABA alone. This has led to the development of several LAMA/LABA fixed-dose combination (FDC) therapies, which provide patients with the convenience of two active compounds in a single inhaler. GFF MDI (Bevespi Aerosphere®) is an FDC of glycopyrrolate/formoterol fumarate 18/9.6 µg formulated using innovative co-suspension delivery technology for administration via metered dose inhaler (MDI). GFF MDI was developed to make a treatment option available for patients who have a requirement or preference to use an MDI, rather than a dry powder or soft mist inhaler. Now that several LAMA/LABA FDCs have been approved for use in COPD, we review the impact of dual-bronchodilator treatment on COPD therapy and discuss recent clinical studies that are helping to develop a more comprehensive understanding of how LAMA/LABA FDCs can improve patient outcomes.

Dual mechanisms of anti-muscarinic and Ca++ antagonistic activities to validate the folkloric uses of Cyperus niveus Retz. as antispasmodic and antidiarrheal.

ETHNOPHARMACOLOGICAL RELEVANCE: Cyperus species are famous for their traditional uses and very commonly used for their anti-spasmodic and anti-diarrheal activities. Cyperus niveus Retz. is used in local traditional system of medicine in Pakistan to treat diarrhea and emesis. AIM OF THE STUDY: The aim of the study was to validate the traditional uses and to provide the possible mechanisms for the medicinal use of Cyperus niveus Retz. as anti-spasmodic, anti-diarrheal and anti emetic. MATERIALS AND METHODS: The in-vivo studies of anti-diarrheal, charcoal meal GI transit test and anti-emetic activities were conducted in rats, mice and chicks respectively, while isolated tissues of rabbit's jejunum and rat's ileum were used for in-vitro experiments. Phytochemical analysis was also undertaken. RESULTS: The phytochemical study of hydro-ethanolic extract of Cyperus niveus Retz. showed the presence of flavonoids, phenols, alkaloids, tannins, saponins and glycosides. Cn. Cr caused significant inhibition of castor oil-induced diarrhea in rats (300,500 & 700mg/kg) using loperamide (10mg/kg, p.o) as standard. Cn. Cr also significantly decreased the motility in charcoal meal GI transit test at 100-200mg/kg in mice, using atropine (3.0mg/kg) as positive control. In jejunum tissue, Cn. Cr relaxed carbachol(1µM) and K+(80mM)-induced contractions, similar to the effect of dicyclomine. Pre-incubation of isolated rat ileum tissues with Cn. Cr (0.1mg/mL) caused the corresponding shift of CCh concentration response curve (CRC) to right without decrease in max. response whereas at the concentration of 0.3mg/mL caused the rightward nonparallel shift with max. response suppression, similar to dicyclomine. Antimuscarinic effect was further confirmed when prior administration of Cn. Cr (0.1, 0.3 and 1mg/mL) caused concentration dependent inhibition of induced contractions of carbachol, comparable to atropine (1µM). To confirm the Ca2+ channel blocking (CCB), the rabbit jejunum was pre-incubated with Cn. Cr (0.3 & 1.0mg/mL), produced a shift in CRCs of calcium toward right with decrease in the maximum response at next concentration, similar to that of dicyclomine. The organic fraction of Cyperus niveus Retz. (Cn. Dcm) showed Ca2+ antagonist and anticholinergic activities with higher potency against K+(80mM) induced contractions, like verapamil, while aqueous fraction (Cn. Aq) relaxed only carbachol(1µM) induced contractions with no prominent effect on K+ (80mM)-contractions even at the higher concentration of 10mg/mL, similar to atropine. Cn. Cr also showed significant anti-emetic effect in Chick emesis model using chlorpromazine as standard. CONCLUSION: This study shows the presence of antidiarrheal and spasmolytic activities in Cyperus niveus Retz. extract, mediated by dual blocking mechanisms of muscarinic receptors and Ca2+ channels. The results further indicate the presence of anti-emetic activity in Cn. Cr, which may be because of its anti-muscarinic potential. This study provides the scientific bases to the traditional use of Cn. Cr in diarrhea and emesis.

The Screening of Anticholinergic Accumulation by Traditional Chinese Medicine.

Many Western drugs can give rise to serious side effects due to their ability to bind to acetylcholine receptors in the brain. This aggravates when they are combined, which is known as anticholinergic accumulation (AA). Some bioactives in Traditional Chinese Medicine (TCM) are known to block acetylcholine receptors and thus potentially cause AA. The AA of TCM was screened by quantifying the displacement of [³H] pirenzepine on acetylcholine receptors in a rat brain homogenate. We used a new unit to express AA, namely the Total Atropine Equivalents (TOAT). The TOAT of various herbs used in TCM was very diverse and even negative for some herbs. This is indicative for the broadness of the pallet of ingredients used in TCM. Three TCM formulas were screened for AA: Ma Huang Decotion (MHD), Antiasthma Simplified Herbal Medicine intervention (ASHMI), and Yu Ping Feng San (YPFS). The TOAT of ASHMI was indicative for an additive effect of herbs used in it. Nevertheless, it can be calculated that one dose of ASHMI is probably too low to cause AA. The TOAT of YPFS was practically zero. This points to a protective interaction of AA. Remarkably, MHD gave a negative TOAT, indicating that the binding to the acetylcholine receptors was increased, which also circumvents AA. In conclusion, our results indicate that TCM is not prone to give AA and support that there is an intricate interaction between the various bioactives in TCM to cure diseases with minimal side effects.

Discovery of new muscarinic acetylcholine receptor antagonists from Scopolia tangutica.

Scopolia tangutica (S. tangutica) is a traditional Chinese medicinal plant used for antispasmodics, anesthesia, analgesia and sedation. Its pharmacological activities are mostly associated with the antagonistic activity at muscarinic acetylcholine receptors (mAchRs) of several known alkaloids such as atropine and scopolamine. With our recent identification of four hydroxycinnamic acid amides from S. tangutica, we hypothesized that this plant may contain previously unidentified alkaloids that may also contribute to its in vivo effect. Herein, we used a bioassay-guided multi-dimension separation strategy to discover novel mAchR antagonists from S. tangutica. The core of this approach is to use label-free cell phenotypic assay to first identify active fractions, and then to guide purification of active ligands. Besides four tropanes and six cinnamic acid amides that have been previously isolated from S. tangutica, we recently identified two new tropanes, one new cinnamic acid amide, and nine other compounds. Six tropane compounds purified from S. tangutica for the first time were confirmed to be competitive antagonists of muscarinic receptor 3 (M3), including the two new ones 8 and 12 with IC50 values of 1.97 µM and 4.47 µM, respectively. Furthermore, the cinnamic acid amide 17 displayed 15-fold selectivity for M1 over M3 receptors. These findings will be useful in designing lead compounds for mAchRs and elucidating mechanisms of action of S. tangutica.

Comparison and evaluation of antimuscarinic and anti-inflammatory effects of five Bulbus fritillariae species based on UPLC-Q/TOF integrated dual-luciferase reporter assay, PCA and ANN analysis.

Many species of Bulbus fritillariae are used as traditional medicines for thousands of years; however, their application is not standardized. To clarify the differences and homologies, the antimuscarinic and anti-inflammatory effects of five BM species were firstly tested and compared at cellular level. With an integrated strategy combining UPLC-Q/TOF MS, PCA and ANN analysis, the active ingredients among 28 different chemical markers were predicted and identified. SB and QB extracts showed the best antimuscarinic effects and several steroidal alkaloids, such as solanidine, contributed to this effects. However, ZB was superior to reduce the inflammatory response. Another five components were responsible by decreasing the expression of NF-κB, including puqiedine, zhepeiresinol, 2-monopalmitin, N-demethylpuqietinone, and isoverticine. More novelty, a new cluster of five BM species based on active ingredients as potential quality markers was depicted to illustrate their functions. These results of the study could make a reference for the medicinal application of BM species in clinic; and the integrated strategy provided an effective method to obtain the quality markers from medical herbs, which was helpful for the quality control of traditional medicinal products.

Discovery of novel quaternary ammonium derivatives of (3R)-quinuclidinyl amides as potent and long acting muscarinic antagonists.

Novel quaternary ammonium derivatives of (3R)-quinuclidinyl amides have been identified as potent M3 muscarinic antagonists with a long duration of action in an in vivo model of bronchoconstriction. The synthesis, structure-activity relationships and biological evaluation of this series of compounds are reported.

Discovery, synthesis and characterization of a highly muscarinic acetylcholine receptor (mAChR)-selective M5-orthosteric antagonist, VU0488130 (ML381): a novel molecular probe.

Of the five G-protein-coupled muscarinic acetylcholine receptors (mAChRs; M1-M5), M5 is the least explored and understood due to a lack of mAChR subtype-selective ligands. We recently performed a high-throughput functional screen and identified a number of weak antagonist hits that are selective for the M5 receptor. Here, we report an iterative parallel synthesis and detailed molecular pharmacologic profiling effort that led to the discovery of the first highly selective, central nervous system (CNS)-penetrant M5-orthosteric antagonist, with sub-micromolar potency (hM5 IC50=450 nM, hM5 Ki=340 nM, M1-M4 IC50>30 µM), enantiospecific inhibition, and an acceptable drug metabolism and pharmacokinetics (DMPK) profile for in vitro and electrophysiology studies. This compound will be a powerful tool and molecular probe for the further investigation into the role of M5 in addiction and other diseases.

Homology modeling of human muscarinic acetylcholine receptors.

We have developed homology models of the acetylcholine muscarinic receptors M1R-M5R, based on the ß2-adrenergic receptor crystal as the template. This is the first report of homology modeling of all five subtypes of acetylcholine muscarinic receptors with binding sites optimized for ligand binding. The models were evaluated for their ability to discriminate between muscarinic antagonists and decoy compounds using virtual screening using enrichment factors, area under the ROC curve (AUC), and an early enrichment measure, LogAUC. The models produce rational binding modes of docked ligands as well as good enrichment capacity when tested against property-matched decoy libraries, which demonstrates their unbiased predictive ability. To test the relative effects of homology model template selection and the binding site optimization procedure, we generated and evaluated a naïve M2R model, using the M3R crystal structure as a template. Our results confirm previous findings that binding site optimization using ligand(s) active at a particular receptor, i.e. including functional knowledge into the model building process, has a more pronounced effect on model quality than target-template sequence similarity. The optimized M1R-M5R homology models are made available as part of the Supporting Information to allow researchers to use these structures, compare them to their own results, and thus advance the development of better modeling approaches.

Evaluation of fesoterodine fumarate for the treatment of an overactive bladder.

INTRODUCTION: Fesoterodine fumarate is an approved drug for overactive bladder. The aim of this study is to review the preclinical and most up to date clinical data on fesoterodine, with a special emphasis on its unique pharmacokinetic features and its implications on safety and tolerability in various patient populations. AREAS COVERED: In this review, the authors extensively reviewed available literature via PubMed search regarding fesoterodine, covering its mechanism of action, pharmacodynamics and pharmacokinetics, clinical efficacy, safety, and tolerability. EXPERT OPINION: Fesoterodine is an anti-muscarinic agent with a unique pharmacokinetic profile. It is a prodrug that is rapidly metabolized to its active form by nonspecific plasma esterases. Its metabolism is independent of the cytochrome P450 enzyme system. This along with its dual excretion pathways and minimal central nervous system penetration leads to less variability in drug exposure and allowance of administration in those with mild to moderate renal and hepatic insufficiency and in the geriatric population.

Inhaled muscarinic acetylcholine receptor antagonists for treatment of COPD.

Bronchodilators, generally administered via metered dose or dry powder inhalers, are the mainstays of pharmacological treatment of stable COPD. Inhaled long-acting beta-agonists (LABA) and anticholinergics are the bronchodilators primarily used in the chronic treatment of COPD. Anticholinergics act as muscarinic acetylcholine receptor antagonists and are frequently preferred over beta-agonists for their minimal cardiac stimulatory effects and greater efficacy in most studies. Their therapeutic efficacy is based on the fact that vagally mediated bronchoconstriction is the major reversible component of airflow obstruction in patients with COPD. However, bronchodilators are effective only on the reversible component of airflow obstruction, which by definition is limited, as COPD is characterized by a fixed or poorly reversible airflow obstruction. Inhaled anticholinergic antimuscarinic drugs approved for the treatment of COPD include ipratropium bromide, oxitropium bromide and tiotropium bromide. Ipratropium bromide, the prototype of anticholinergic bronchodilators, is a short-acting agent. Oxitropium bromide is administered twice a day. Tiotropium bromide, the only long-acting antimuscarinic agent (LAMA) currently approved, is administered once a day. Newer LAMAs including aclidinium bromide and glycopyrrolate bromide are currently in phase III development for treatment of COPD. Some new LAMAs, including glycocpyrrolate, are suitable for once daily administration and, unlike tiotropium, have a rapid onset of action. New LAMAs and their combination with ultra-LABA and, possibly, inhaled corticosteroids, seem to open new perspectives in the management of COPD. Dual-pharmacology muscarinic antagonist-beta2 agonist (MABA) molecules present a novel approach to the treatment of COPD by combining muscarinic antagonism and beta2 agonism in a single molecule.

The discovery of AZD9164, a novel muscarinic M3 antagonist.

The optimization of a new series of muscarinic M(3) antagonists is described, leading to the identification of AZD9164 which was progressed into the clinic for evaluation of its potential as a treatment for COPD.

Enantiomeric differentiation of atropine/hyoscyamine by (13) C NMR spectroscopy and its application to Datura stramonium extract.

INTRODUCTION: The two enantiomers of hyoscyamine, an alkaloid found in many plant species, have distinct pharmacological and biological properties. Methods for the discrimination of both enantiomers are almost exclusively based on chiral HPLC/UV. Determination of the enantiomeric ratio (e.r.) of hyoscyamine is a challenging problem since this compound tends to racaemise, forming atropine during acid-base extraction. OBJECTIVE: To develop a protocol for the calculation of enantiomeric ratio of hyoscyamine in a plant extract using a (13) C NMR method. METHODOLOGY: Samples were prepared by extraction of dried Datura stramonium seeds. Observation of C12 and C15 NMR signals of hyoscyamine in the presence of one equivalent of TFA and sub-stoichiometric amount of Yb(hfc)(3) allowed the calculation of the e.r. of S-(-) and R-(+)-hyoscyamine.The method was optimised with various mixtures of (+) and (-)-hyoscyamine ranging from 50:50 (racaemic mixture, i.e. atropine) to 98.5:1.5. The e.r. measured by NMR on the signals of aromatic C12 and C15 were in agreement with the gravimetrically prepared samples. The method was then applied to an extract of Datura stramonium and S-(-)-hyoscyamine was the unique enantiomer. CONCLUSION: The study showed that the e.r. determination of atropine/hyoscyamine was achieved with a routine NMR spectrometer, using CLSR/TFA on pure compounds as well as on the crude extract of Datura stramonium.

Discovery of novel 8-azoniabicyclo[3.2.1]octane carbamates as muscarinic acetylcholine receptor antagonists.

In the course of our research program to develop novel muscarinic receptor antagonists for the treatment of COPD, new tropane carbamate derivatives were identified as potent anti-muscarinic agents. The synthesis, structure-activity relationships and pharmacological evaluation that led to the identification of compound 5o, are described.

Novel oxotremorine-related heterocyclic derivatives: Synthesis and in vitro pharmacology at the muscarinic receptor subtypes.

A set of novel heterocyclic ligands (6-27) structurally related to Oxotremorine 2 was designed, synthesized and tested at muscarinic receptor subtypes (mAChRs). In the binding experiments at cloned human receptors (hm1-5), compounds 7 and 15 evidenced a remarkable affinity and selectivity for the hm2 subtype. The in vitro functional assays, performed on a selected group of derivatives at M(1), M(2), and M(3) tissue preparations, singled out the 3-butynyloxy-5-methylisoxazole trimethylammonium salt 7 as a potent unselective muscarinic agonist [pEC(50): 7.40 (M(1)), 8.18 (M(2)), and 8.14 (M(3))], whereas its 5-phenyl analogue 12 behaved as a muscarinic antagonist, slightly selective for the M(1) subtype [pK(B): 6.88 (M(1)), 5.95 (M(2)), 5.53 (M(3))]. Moreover, the functional data put in evidence that the presence of the piperidine ring may generate a functional selectivity, e.g., an M(1) antagonist/M(2) partial agonist/M(3) full agonist profile (compound 21), at variance with the corresponding quaternary ammonium salt (compound 22) which behaved as a muscarinic agonist at all M(1-3) receptors, with an appreciable selectivity for the cardiac M(2) receptors.

Structure-activity relationships of methoctramine-related polyamines as muscarinic antagonist: effect of replacing the inner polymethylene chain with cyclic moieties.

The aim of the present paper was to investigate the role of the octamethylene spacer of methoctramine (1) on the biological profile. Thus, this spacer was incorporated into a dianiline or dipiperidine moiety to determine whether flexibility and the basicity of the inner nitrogen atoms are important determinants of potency with respect to muscarinic receptors. The most potent compound was 4, which displayed, in the functional assays, a comparable potency at muscarinic M(2) receptors with respect to 1, and, in the binding assays, a loss of potency and selectivity toward muscarinic M(1) and M(3) receptor subtypes. Both compounds were endowed with antinociceptive activity. Furthermore, in microdialysis tests in rat parietal cortex, they enhanced acetylcholine release, most likely by antagonizing presynaptic muscarinic receptor subtypes.

Bonabiline A, a monoterpenoid 3alpha-acyloxytropane from the roots of Bonamia spectabilis showing M3 receptor antagonist activity.

Two 3alpha-acyloxytropanes with unique monoterpenoic acyl moieties, bonabiline A and its anhydro derivative bonabiline B, have been isolated from the roots of Bonamia spectabilis. Their structures were elucidated by detailed spectroscopic analysis. Due to the structural similarity of bonabiline A to atropine/hyoscyamine, the affinity of both bonabilines to the muscarinic M (3) receptor was studied in the isolated guinea-pig ileum. Bonabiline A (pA (2) 6.65 +/- 0.03) proved to be a more potent antagonist than bonabiline B (pA (2) 5.50 +/- 0.03).

Phytochemical screening and effect of aqueous extract of Ficus sycomorus L. (Moraceae) stembark on muscular activity in laboratory animals.

The stembark of Ficus sycomorus was collected, dried and extracted, to screen for some chemical constituents and study its effect on muscle contraction. The duodena and recti abdominis of 10 guinea pigs weighing between 330 and 345 g and 10 frogs weighing between 180 and 201 g, respectively, were isolated and used for this study. The extract was tested to see its effect on acetylcholine (ACH) induced contraction on kymograph. The extract reduced the acetylcholine contractile responses of guinea pigs duodena and recti abdominis muscles of frogs significantly, thus showing inhibitory effect on muscle contraction. The extract showed the presence of gallic tannins, saponins, reducing sugars, alkaloids and flavone aglycones. It was concluded that the extract has inhibitory effect on both smooth and skeletal muscles contractions and contains important constituents for pharmacological activities.