Fescue toxicosis is problematic for ruminant livestock, causing weight loss and low productivity when fed endophyte-infected forages. Complete underlying mechanisms of toxicosis are unknown therefore; the objective of the study was to determine if ruminally dosed ergot alkaloids impact rumen motility. Cannulated steers were pair-fed a forage diet and ruminally dosed with endophyte-free (E-) or endophyte-infected (E+) tall fescue seed. An 8-h period of rumen motility collection began 4-h after feeding by monitoring pressure change via a wireless telemetry and transducer system. In experiment 1, steers were paired by weight and assigned to E- or E+ treatment. Overall, E+ steers had more frequent contractions. On d 7 - 9, both treatments had lower frequencies and E- steers had greater amplitude of contractions, which corresponded with decreased DM intake. In experiment 2 steers remained in pair, but switched treatment. During the 57 d E+ steers received titrated levels of ergovaline + ergovalinine. There was no difference between treatments for frequency or amplitude of contractions, but increasing dosage, decreased frequency (d 1 - 44) and amplitude, coinciding with lower DM intakes. Alteration in rumen motility associated with changes in intake may be responsible for the decreased productivity in ruminants consuming E+ forages.

No description available.

The present investigation has involved a kinetic and mechanistic study of the thermal cyclization of 3-acetoxy-3-(2-pyridyl)-2-methylenepropanoate esters and related compounds to 2-substituted indolizines. Substrates for the kinetic study were prepared via the Baylis-Hillmann reaction of pyridine-2-carboxaldehydes with acrylate esters, acrylonitrile and methyl vinyl ketone. The resulting hydroxy compounds were then acetylated to afford the acetoxy derivatives, thermal cyclization of which gave the corresponding 2-substituted indolizines. The cyclization reactions was followed using 'H NMR spectroscopy and were shown to follow firstorder kinetics. The influence of the various substituents on the observed first-order rate constants has been examined and variable temperature studies have permitted evaluation of activation parameters for the formation of methyl indolizine-2-carboxylate and ethyl indolizine-2-carboxylate. An alternative route to 2-substituted indolizines via halogenated derivatives was explored and several halogenated 2-pyridyl derivatives were synthesised and their thermal cyclization to indolizines was attempted. Novel 5-methylindolizine-2-carboxamides were prepared as part of this investigation and dynamic NMR spectroscopy was used to study internal rotation about the amide N-CO bond in these compounds.

The crystalline compound resulting from thermal cyclization of the Baylis-Hillman product, methyl 3-hydroxy-2-methylene-3-(2-pyridyl)propanoate, has been identified as the indolizine derivative, methyl indolizine-2-carboxylate, and this approach involving the reaction of pyridine-2-carboxaldehydes and acrylate analogues has been established as a general route to 2-substituted indolizines. The ease of cyclization the Baylis-Hillman products to indolizines has been shown to increase by converting the hydroxy group to an acetoxy group, and a range of acetylated Baylis-Hillman products were prepared and cyc1ized to the corresponding 2-substituted indolizines, generally in good overall yield. In the reaction of pyridine-2-carboxaldehyde and methyl vinyl ketone, the intermediate cyclized readily and directly to the corresponding indolizine. One- and two-dimensional ¹H and ¹³C NMR analysis of the 2-substituted indolizine products has permitted complete assignment of all ¹H and ¹³C NMR signals, as well as the measurement of all coupling constants for these compounds. A kinetic and mechanistic study has been conducted on the Baylis-Hillman reaction using ¹H NMR spectroscopy. A range of substrates has been examined and the reaction has been found to be third-order overall. A mechanism involving an addition - elimination sequence is proposed, which fits the kinetic data and accounts for observed substituent effects. Reaction of N,N-dimethylacrylamide with pyridine-2-carboxaldehyde in the presence of the tertiary amine catalyst, DABCO, in chloroform, yielded an unexpected product which has been identified by single crystal X-ray diffraction analysis as 1-(2,2,2-trichloro-1-hydroxyethyl)pyridine. Attempted extension of the general indolizine route to the preparation of chromene systems by reacting salicylaldehyde with methyl acrylate in the presence of DABCO, also led to an unexpected, crystalline material, identified by single crystal X-ray diffraction analysis as the coumarin derivative, 3-[(2-formylphenoxy)methyl]coumarin.A series of chloroquine analogues have been prepared from indolizine-2-carboxylic acid, pyrrolo[I,2-a]quinoline-2-carboxylic acid and imidazo[I,2-a]pyridine-2-carboxylic acid by reaction with suitable amines in the presence of the coupling reagent 1, I' -carbonyldiimidazole. This route has been shown to be a vast improvement on earlier procedures and has provided access to both secondary and tertiary indolizine-2-carboxamides. A range of N,N-dialkylindolizine-2-carboxamides have been prepared by this route, and the influence of substituents on their N-CO rotational energy barriers has been determined using variable temperature ¹H and ¹³C NMR techniques. Intercalation with natural DNA by both chloroquine and the synthesized chloroquine analogues has been examined using UV spectrophotometry, and ¹H and ³¹P NMR spectroscopy. The pyrrolo[I,2-a]quinolines have been shown to be DNA intercalators with binding affinities similar to that of the known antimalarial intercalator, chloroquine. In a preliminary study the synthesis of a short oligonucleotide has been undertaken and changes have been observed in the ¹H and ³¹P NMR spectra of the oligonucleotide on addition of the intercalator, chloroquine.

CONTEXT: The seeds from Lupinus mutabilis Sweet, also called “chocho”, are an important part of the diet in several countries in South America. Prior to consumption, processing is required to remove toxic alkaloids. These alkaloids are known to have pharmacological properties as antiarrhythmics, antimuscarinics and hypoglycemics. CASE REPORT: We report a case in which a one-year-old male initially presented with altered mental status and respiratory distress and subsequently developed symptoms of anticholinergic toxicity, after ingesting a large amount of chocho seeds. CONCLUSION: In spite of going through a difficult clinical condition, the subject evolved favorably through receiving supportive treatment. The seeds from Lupinus mutabilis provide nutritional benefits when consumed, but people need to know their risks when these seeds are consumed without proper preparation.

Hydroamination stands as a desirable approach to nitrogen-containing molecules, which have important applications ranging from pharmaceuticals (fine chemicals) to paints, coatings, insecticides and agrochemicals (bulk chemicals). It features the use of alkene and alkyne starting materials, which are abundant and rarely used in the formation of C-N bonds. This work aims at building on the improved Cope-type reactivity developed in the Beauchemin group by expanding the reach of the reaction and understanding its mechanistic complexities. The first part of this thesis describes the development of cascade reactions to provide a thermodynamic driving force for the intermolecular Cope-type hydroamination of alkenes. The methodology serves as a proof of concept that the dipolar reaction intermediates can be engineered to further react irreversibly to more stable products, and has shown potential in improving the syntheses of natural alkaloids. The second part of the thesis describes the expansion of Cope-type hydrazide hydroaminations through a systematic investigation of hydrazine analogs as reactants. Optimized reagents are featured in the first reported intermolecular Cope-type hydrohydrazidation of alkenes. Mechanistic investigations and isolation of ammonium ylide intermediates support a 5-membered concerted and planar mechanistic pathway for hydrazide hydroaminations, similar to that observed with hydroxylamines. The final section presents mechanistic data disproving a previously assumed difficult proton transfer step in the hydroamination using hydroxylamines. From such findings, early results are presented towards a hydrogen-bond catalyzed hydroamination, which has potential applicability across the field of Cope-type hydroaminations and beyond.

This thesis describes the synthesis of novel analogs of the unique opioid receptor modulator mitragynine along with pharmacological and behavioral studies of a subset of its novel analogs. In Chapter 1, a general overview of opioid receptors and the importance of the mu opioid receptor (MOR) for the treatment of pain is provided. The rise of the opioid epidemic is discussed which brings into attention the need to develop safer opioid therapeutics for the treatment of pain. In this regard the Mitragyna indole alkaloids, isolated from kratom leaves are of great interest as they are considered to be “atypical” opioid ligands and represent novel molecular scaffolds for the development of safer opioid receptor modulators. The introductory chapter includes a brief description of the pharmacological profile of mitragynine as a prelude to the work that follows – examining unexplored positions on the alkaloid by devising new methodology and synthetic routes to synthesize novel analogs to study its structure-activity relationship (SAR) at the opioid receptors. Chapter 2 describes the development of a new synthetic method for selective functionalization of the unexplored C11 position of the MG scaffold (C6 position in indole numbering). The method takes advantage of an indole-ethylene glycol adduct as a key intermediate which can undergo subsequent iridium-catalyzed borylation at the desired position. This late-stage C(sp2)-H functionalization approach provides a practical route to novel C11-analogs of mitragynine and related scaffolds starting from the natural product, thus allowing a systematic SAR exploration of the C11 position. Chapter 3 directly builds on Chapter 2, summarizing the neuropharmacological and behavioral studies on the C11 analogs of 7-hydroxymitragynine (7OH) and mitragynine ethylene glycol (MG-EG). Through these studies we discover that the C11 position represents a key locant for fine-tuning opioid receptor signaling efficacy. We also discuss that the parent 7-hydroxymitragynine (7OH), a low efficacy agonist, is transformed to an even lower efficacy agonist by introducing a fluorine substituent at the C11 position (11-F-7OH). This is demonstrated in vitro at both mouse and human mu opioid receptors (mMOR/hMOR) and in vivo in mouse analgesia tests. Low efficacy opioid agonists are of high interest as candidates for generating safer opioid therapeutics with mitigated side effects. Thus, this section concludes with the identification 11-F-7OH as lead compound for future investigation. Chapter 4 describes our attempts towards the functionalization of another unexplored and vital position for the activity of mitragynine at the mu opioid receptor (MOR) – the ethyl group at the C20 position. This chapter illustrates our extensive efforts towards the late-stage functionalization of the ethyl group in the C20 position of mitragynine via directed C(sp3)-H activation. Various strategies including using the mitragynine ethylene glycol (MG-EG) as a bidentate ligand or manipulating the acrylate ester group on mitragynine as a directing group are discussed in the chapter. Also described are all the screened reaction conditions using palladium catalysts and various ligands starting from pyridine-based to mono-protected amino acid-based ligands. The outcomes and hypotheses for the failures of each strategy employed are also presented in the chapter. Chapter 5 describes our efforts towards the de novo synthesis of the C20 analogs, as an alternative strategy to the failed late-stage functionalization from Chapter 4. We present a strategy to synthesize the C20 analogs through a diversification strategy from a common intermediate. We further discuss the results of our efforts towards the formal synthesis of this common intermediate. The chapter concludes with a discussion of an alternate strategy for the synthesis of the C20 analogs.

This diploma thesis was focused on basic physicochemical properties of caffeine and investigation of the interaction between the polysaccharide sodium hyaluronan (HA), pectin (PEC) or lignohumate (HUM) and the alkaloid caffeine (CAF). The reason why this thesis was focused on study of aqueous solutions of hyaluronan or pectin with caffeine is that the presence of polysaccharide- caffeine complex could be beneficial for slowing the absorption of caffeine. In the theoretical part of the diploma thesis there is described a group of alkaloids, which caffeine belongs to and also polysaccharides hyaluronic acid and pectin. The most attention has been paid to caffeine, its properties and effects on the human organism. This diploma thesis also deals with non-alcoholic beverages with caffeine, 4-methylimidazole, and phosphoric acid. The last chapter of the theoretical part is dedicated to fluorescence spectroscopy. In the experimental part of this work I deal with the basic properties of caffeine and interaction between the caffeine and selected polysaccharides or lignohumate. At first, the chemical and physical properties of caffeine were determined. Based on these results the interaction of caffeine and hyaluronan or pectin was studied by using the fluorescence and absorbance. The HA of molecular weight of 1,7 MDa and pectin from citrus fruits were chosen for the study of the interaction with the caffeine. These two substances were mixed with the caffeine of concentration contained in Coca-Cola. The results of interaction that would lead to the influence of the emission or absorption properties of caffeine, were not proved. As a part of the work there was determined how pectin behaves in strongly acidic solution and then there was monitored the pH, conductivity and solubility of caffeine in water by using thermogravimetry and visual experiments. The obtained results of the interaction of hyaluronan-caffeine, pectin caffeine or caffeine-lignohumate can be used for description of the behavior of caffeine in the presence of selected polysaccharides and natural organic substance.

Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Botany Candidate: Adéla Potůčková Supervisor: doc. Ing. Lucie Cahlíková, Ph.D. Title of diploma thesis: Derivatives of Amaryllidaceae alkaloids and their biological activity The plants of Amaryllidaceae family are source of a large amount of biologically active substances called Amaryllidaceae alkaloids. Their effects include cytotoxic, antifungal, antiviral, antibacterial or antimalaric activity and, last but not least, the inhibition of cholinesterases. The Amaryllidaceae alkaloids, galanthamine type also includes alkaloid chlidanthine, which is a positional isomer of the clinically practice used alkaloid galanthamine. The sources of chidanthine are Chlidanthus fragrans, Haemanthus multilflorus and Hippeastrum aulicum. The object of this thesis was the preparation of chlidanthine derivatives, and the study of their biological activity connected to the therapy of Alzheimer's disease and cancer. Ten aromatic ester derivatives of chlidanthine were prepared. The chemical structures were elucidated by NMR, MS experiments and optical rotation. Most derivatives were screened for their AChE and BuChE inhibitory potential and their cytotoxic potential against a panel of tumor and non-tumor cell lines. The most...

Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Botany Candidate: Bc. Lenka Loskotová Supervisor: doc. Ing. Kateřina Macáková, Ph.D. Title of Thesis: Interactions of alkaloids with transition metals IV. Copper is a biogenic trace element that participates in the proper function of an organism. It is part of a number of enzymes and participates in metabolic processes in the human body. The level of copper in the organism should be regulated to avoid its excess or deficit, as pathologies could occur. Alkaloids are natural nitrogenous substances of alkaline nature. We find many biological activities in them. The aim of this thesis was to measure copper-chelating and copper- reducing activity of isoquinoline alkaloids: corypalmine, thalictricavine, 8-oxoberberine, fumarilin, norisocorydine and laurotetanine. Alkaloid activity was measured at different pH environments (4.5; 5.5; 6.8 and 7.5) and in the DMSO environment by a spectrophotometric method using hematoxyline and acid disodium salt bathocuproindisulfonic. Based on the results, structure-effect relationships were derived. In experimental measurement, it was found that none of us tested alkaloids showed chelating activity. Reduction activity has been demonstrated in all test substances. The lowest activity...