Parkinson’s disease (PD) is an age-related neurodegenerative disorder. The degeneration of the neurons of the substantia nigra in the midbrain leads to the loss of dopamine from the striatum, which is responsible for the motor symptoms of PD. In the brain, the enzyme, monoamine oxidase B (MAOB), An analysis of the Lineweaver-Burk plots indicated that 7-(3-bromobenzyloxy)-3,4-dihydro-2(1H)- quinolinone inhibits MAO-B with a Ki value of 2.7 nM. An analysis of the structure-activity relationships for MAO-B inhibition shows that substitution on the C7 position of the 3,4-dihydro- 2(1H)-quinolinone moiety leads to significantly more potent inhibition compared to substitution on C6. In this regard, a benzyloxy substituent on C7 is more favourable than phenylethoxy and phenylpropoxy substitution on this position. In spite of this, C6-substituted 3,4-dihydro-2(1H)-quinolinone with potent MAO-B inhibitory activities were also identified. An analyses of selected properties of the 3,4-dihydro-2(1H)- quinolinones showed that the compounds are highly lipophilic with logP values in the range of 3.03- 4.55. LogP values between 1 and 3 are, however, in the ideal range for bioavailability. The compounds synthesised have logP values higher than 3, which may lead to lower bioavailability. Laboratory data further showed that none of the 3,4-dihydro-2(1H)-quinolinones are highly toxic to cultured cells at the concentrations, 1 μM and 10 μM, tested. For example, the most potent MAO-B inhibitor, 7-(3-bromobenzyloxy)-3,4-dihydro-2(1H)-quinolinone, reduced cell viability to 88.11% and 86.10% at concentrations of 1 μM and 10 μM, respectively. These concentrations are well above its IC50 value for the inhibition of MAO-B. At concentrations required for MAO-B inhibition, the more potent 3,4-dihydro-2(1H)-quinolinones are thus unlikely to be cytotoxic. It may thus be concluded that C7-substituted 3,4-dihydro-2(1H)-quinolinones are promising highly potent and selective MAO-B inhibitors, and thus leads for the therapy of Parkinson’s disease. represents a major catabolic pathway of dopamine. Inhibitors of MAO-B conserve the depleted supply of dopamine and are thus used in the therapy of PD. In the present study, a series of 3,4- dihydro-2(1H)-quinolinone derivatives were synthesized and evaluated as inhibitors of recombinant human MAO-A and MAO-B. These quinolinone derivatives are structurally related to a series of coumarin (1-benzopyran-2-one) derivatives, which has been reported to act as MAO-B inhibitors. C6- and C7-substituted 3,4-dihydro-2(1H)-quinolinone derivatives were synthesized by reacting 6- or 7- hydroxy-3,4-dihydro-2(1H)-quinolinone with an appropriately substituted alkyl bromide in the presence of base. To evaluate the MAO inhibitory properties (IC50 values) of the quinolinone derivatives the recombinant human MAO-A and MAO-B enzymes were used. The reversibility of inhibition of a representative 3,4-dihydro-2(1H)-quinolinone derivative was examined by measuring the recovery of enzyme activity after the dilution of the enzyme-inhibitor complexes, while the mode of MAO inhibition was determined by constructing Lineweaver-Burk plots. To determine the lipophilicity of the 3,4-dihydro-2(1H)-quinolinone derivatives, the logP values were measured. The toxicity of the 3,4-dihydro-2(1H)-quinolinone derivatives towards cultured cells (cytotoxicity) was also measured. The results document that the 3,4-dihydro-2(1H)-quinolinone derivatives are highly potent and selective MAO-B inhibitors with most homologues exhibiting IC50 values in the nanomolar range. The most potent MAO-B inhibitor, 7-(3-bromobenzyloxy)-3,4-dihydro-2(1H)-quinolinone, exhibits an IC50 value of 2.9 nM with a 2750-fold selectivity for MAO-B over the MAO-A isoform. As a MAO-B inhibitor, this compound is approximately equipotent to the most potent coumarin derivative (IC50 = 1.14 nM) reported in literature. Since MAO-B activity could be recovered after dilution of enzyme-inhibitor mixtures, it may be concluded that 7-(3-bromobenzyloxy)-3,4-dihydro-2(1H)- quinolinone is a reversible MAO-B inhibitor. The Lineweaver-Burk plots constructed for the inhibition of MAO-B by 7-(3-bromobenzyloxy)-3,4-dihydro-2(1H)-quinolinone were linear and intersected on the y-axis. These data indicated that this compound also is a competitive MAO-B inhibitor. / MSc (Pharmaceutical Chemistry), North-West University, Potchefstroom Campus, 2014

Ce manuscrit décrit la synthèse et l'évaluation biologique d'analogues de l'ω-agatoxine IVB dans le but de trouver de nouveaux outils pour l'étude de l'activité des canaux calciques. L'ω-agatoxine IVB est une neurotoxine peptidique isolée du venin d'araignée Agelenopsis aperta qui à ce jour est l'inhibiteur spécifique et sélectif des canaux calciques voltage-dépendants de type P/Q. Ces canaux sont impliqués dans la neurotransmission dépendante du Glutamate dans le système nerveux central. La synthèse de structures peptidiques simplifiées, en comparaison avec celle de la toxine native est décrite. La méthodologie de synthèse de différents analogues cycliques de cette neurotoxine est présentée. Les composés sont synthétisés par synthèse peptidique sur phase solide en stratégie Fmoc, avec une étude particulière sur les conditions de cyclisation et le choix des groupements protecteurs appropriés. Les modifications d es peptides naturels pour obtenir de nouveaux composés biologiquement actifs incluent l'insertion d'aminoacides non naturels et de liaisons pseudopeptidiques. Les analogues synthétisés ont été testés par des méthodes d'électrophysiologie (patch clamp) et d'imagerie calcium ; les activités biologiques des peptides sont corrélées à l'aide d'analyses structurales par RMN et modélisation moléculaire. / This manuscript describes the synthesis and biological valuation of w-agatoxin IVB mimetics with the intention of finding new tools for the study of calcium channels activity. w-Agatoxin IVB is a peptide neurotoxin isolated from the venom of spider Agelenopsis aperta which is a specific and selective inhibitor of P/Q-type voltage-dependent calcium channels. These channels are involved in Glutamate-dependent neurotransmission in the central nervous system. The synthesis of structurally simplified peptides, in comparison with native toxin is described. The methodology of synthesis of different cyclic analogues of this neurotoxin is presented. The compounds were synthesized by solid phase peptide chemistry and Fmoc strategy, with particular consideration for cyclization conditions and an insight into selection of protecting groups. The modifications of the natural peptide to get new biologically active compounds included the insertion of unnatura l amino acids and pseudopeptides bonds. The synthesized analogues were tested by methods of electrophysiology (patch clamp) and calcium imagery; the biological activities of peptides are compared with the aid of structural analyses by RMN and molecular modeling.

English abstract Glutamate carboxypeptidase II (GCPII, EC 3.4.17.21) is a membrane bound glycoprotein that belongs to the metallopeptidase M28 family. Two physiological substrates were found for GCPII. The first one, N-acetyl-aspartylglutamate (NAAG), serves as a neurotransmiter in the brain and GCPII hydrolyzes it to yield free glutamate in the synaptic cleft. Excess glutamate might be cytotoxic and eventually lead to excitoxic nerve cells death. Inhibition of NAAG hydrolyzing activity has been shown to be neuroprotective. Therefore, GCPII inhibition was suggested as a therapeutic target in treatment of neurological disorders where excess glutamate is involved. The second substrate, polyglutamyl folate, is a precursor of folic acid which is required for cell growth and development. GCPII cleaves off glutamate from dietary folates and thus facilitates their absorption in small intestine. Although GCPII biological relevance is known only in the brain and the small intestine, its role in the prostate is also important. GCPII has been described as a prostate cancer marker as it is expressed on the membrane of prostate cancer cells. Since GCPII is type II transmembrane protein, it is enzymatically active and undergoes internalization, it has been suggested as a promising tool for specific anticancer-drug...

Preparou-se, neste trabalho, nove cloridratos de N,N- [(dimetilamino)metil]benzamidas-p-X-substituidas em que X = N02, Br, Cl, I, F, H, CH3, OCH3 e N(CH3)2, SÉRIE II, ainda não descritos na literatura, a partir das respectivas bases, SÉRIE I. Os compostos obtidos foram identificados por seus espectros de I.V e RMN1H, e suas purezas determinadas por análise elementar e ponto de fusão. A seguir, determinou-se os valores de vC=O (cm-l ) em HCCl3, como medida de sua polaridade tanto para os compostos da SÉRIE I como para os da SÉRIE II. A aplicação da equação de HAMMETT, simples e expandida, aos valores obtidos forneceu excelentes correlações, verificando-se que os efeitos eletrônicos que os substituintes exercem sobre o grupo carbonila são de natureza indutiva e de ressonância, não havendo predominância de um sobre o outro. Determinou-se também, por bloqueio nervoso periférico em pata de rato, o grau de atividade anestésica local de sete dos nove compostos da SÉRIE II. A aplicação da equação de HANSCH aos valores de atividade anestésica local mostrou haver correlação razoável considerando-se os efeitos eletrônicos e hidrofóbicos exercidos pelos substituintes. A análise dos coeficientes de regressão obtidos sugere haver contribuição preponderante dos efeitos eletrônicos em relação à contribuição do efeito hidrofóbico para a atividade anestésica local. / In the present work nine N,N-[(dimethyl amino)methyl]benzamides-p-X-substituededs hydrochlorides (SERIES II) were prepared from the corresponding bases, (SERIES I), where X = N02, Br, Cl, I, F, H, CH3, OCH3 and N(CH3)3. The purity of the novel compounds, SERIES II, was established by elemental analysis. The recorded infrared and 1HNMR spectra were in agreement with their structures. For both sets of compounds the carbonyl group infrared frequencies in HCCl3 were determined and used as measurement of the polarity of the group. The obtained vC=O (cm-1) values showed excellent correlations when a simple or a multiparameter HAMMETT equation was applied. This suggests that the eletronic effect of the substituents on the carbonyl stretching frequencies is of inductive and ressonanee nature, without predominances of one over the other. Were also determined by peripheryc nervous blockade on rats paw, the degree of local anesthetic activity on seven of the nine compounds of SERIES II. The application of the HANSCH equation to the local anesthetie activity values showed reasonable correlation when the eletronic and hydrophobic effects of the substituents were considered. Analysis of the obtained regression coefficents suggest that the contribution of the former effect to the local anesthetic activity predominants.

As estruturas e propriedades biológicas das amidas piplartina e a piperina, isoladas respectivamente de Piper tuberculatum e P. nigrum, inspiraram a síntese de 89 derivados e 7 esters estruturalmente relacionadas. As preparações envolveram metodologias tradicionais e os compostos purificados tiveram suas estruturas caracterizadas por análises espectroscópicas e espectrométricas. Os estudos de fragmentação por IE e IES indicaram a clivagem preferencial da ligação N-CO no caso das cinamamidas, dienamidas e cinamimidas. Estudos computacionais envolvendo afinidade protônica e energias de ligação confirmaram a fragmentação preferencial da ligação amídica para as amidas. A citotoxicidade de 89 substâncias foi avaliada contra três células leucêmicas (K562, Nalm6 e Raji) e a partir dos valores de IC50 foram realizados estudos de relação estrutura-atividade (SAR). As linhagens K562 e a Nalm6 foram a mais resistente e vulnerável, respectivamente, e as amidas piplartina (1a), N-Ciclohexil-N-(ciclohexilcarbamoil)-3-(3,4,5-trimetoxifenil)propanamida (1n), e (E)-N,N-dibutil-3-(3,4-dimetoxifenil)acrilamida (13h) foram as mais ativas com IC50 de 0,34 µM; 0,84 µM e 1,88 µM contra K562 e (E)-N-ciclohexil-N-(ciclohexilcarbamoil)-3-(3,4-dimetoxifenil)acrylamida (13i) com IC50 de 0,98 µM contra Nalm6. A avaliação de atividade leishmanicida de 18 substâncias não se mostrou promissora. As abordagens qualitativas e quantitativas foram feitas baseadas nos descritores moleculares gerados pelo programa VolSurf+. A partir de métodos quimiométricos tais com PLS, algoritmo genético, árvores de decisão foi possível gerar modelos para correlacionar às propriedades moleculares com a atividade biológica. As propriedades de absorção, distribuição, metabolismo e excreção e os equilíbrios entres as regiões hidrofílicas e hidrofóbicas foram importantes para atividade citotóxica. O estudo de ancoragem molecular mostrou que as amidas (E)-N,N-dibutil-3-(3,4,5-trimetoxifenil)acrilamida (1l), 1n, (E)-3-(4-clorofenil)-N-ciclohexil-N-(ciclohexilcarbamoil)acrilamida (5a), 13h e 13i podem atuar como inibidores das histonas desacetilases particularmente HDAC4 e HDAC8. / The structures and biological properties of the amides piplartine and piperine isolated from Piper tuberculatum and P. nigrum respectively, inspired the synthesis of derivatives 89 and 7 esters structurally related. Their preparations were achieved using classical procedures and the purified amides were submitted to spectroscopic and spectrometric characterization. The study of fragmentation process by EI and ESI suggested the preferential cleavage of the N-CO bond of cinnamamides, dienamides and cinnamimides. The cytotoxicity of 89 compounds was evaluated against three leukemic cells (K562, Nalm6 and Raji) and based on IC50 values the structure-activity relationship (SAR) was performed. While the K562 and Nalm6 cells were the more resistant and more sensitive, respectively, the amides piplartine (1a), N-cyclohexyl-N-(ciclohexylcarbamoyl)-3-(3,4,5-trimethoxyphenyl)propanamide (1n) and (E)-N,N-dibutyl-3-(3,4-dimethoxyphenyl)acrylamide (13h) were in general the most active with IC50 of 0.34 µM, 0.84 µM and 1.88 µM against K562 and (E)-N-cyclohexyl-N-(ciclohexylcarbamoyl)-3-(3,4-dimethoxyphenyl)acrylamide (13i) with IC50 of 0.98 µM against Nalm6. The evaluation of leishmanicidal activity of 18 substances was also performed but was not promising. Qualitative and quantitative approaches were made based on molecular descriptors generated by VolSurf+ program. The chemometric methods such as PLS, genetic algorithm, decision trees generated models to correlate molecular properties with the biological activity. The absorption, distribution, metabolism and excretion properties and a balance between hydrophilic and hydrophobic moieties of the amides were important for an optimized activity. The molecular docking revealed that amides such as (E)-N,N-dibutyl-3-(3,4,5-trimethoxyphenyl)acrylamide (1l), 1n, (E)-3-(4-chlorophenyl)-N-cyclohexil-N-(cyclohexylcarbamoyl)acrylamide (5a), 13h and 13i have potential to act as possible inhibitors of histone deacetylase proteins particularly HDAC4 and HDAC8.

A hemoglobina (Hb) é uma fonte reconhecida de peptídeos com funções biológicas diversas. O fragmento 33-61 da cadeia α da Hb, isolado do trato gastrointestinal do carrapato Boophilus microplus, foi o primeiro a ser descrito com ação antimicrobiana. O seu análogo sintético amidado, Hb33-61a, mostrou-se ativo contra bactérias Gram-positivas e fungos [Fogaça et al. (1999) J. Biol. Chem. 274, 25330-4]. O estudo de análogos do Hb33-61 nas formas amidada e com carboxila livre revelou que a amidação provoca aumento significativo da atividade frente a Candida albicans. Por apresentar propriedades biológicas e estruturais idênticas às do Hb33-61a, o Hb40-61a pareceu ser a sua porção mÌnima ativa [Sforça et al. (2005) Biochemistry 44, 6440- 51; Machado et al. (2007) Biopolymers 88, 413-26]. Para comprovar tal sugestão, no presente trabalho, sintetizamos, purificamos e caracterizamos novos an·logos do Hb33-61a, bem como os avaliamos quanto às suas atividades frente a C. albicans e Micrococcus luteus. Os resultados confirmaram a sugestão apenas para a ação antifúngica. O análogo Hb40-61a também se mostrou ativo frente a C. albicans resistente a fluconazol. A sua atividade antifúngica se mostrou fortemente dependente da força iônica do meio. A sua baixa atividade hemolítica foi confirmada mesmo em meio de baixa força iônica. O peptídeo Hb40-61a não apresentou sinergismo com o fluconazol frente a C. albicans. A cinética de morte celular mostrou que ele mata a levedura de forma rápida. Portanto, esta hemocidina sintética pode apresentar valor comercial se a via de administração for tópica ou se o seu uso envolver meios de baixa força iônica. Além disso, ela é um modelo valioso para o estudo do mecanismo de ação de peptídeos antimicrobianos com características estruturais similares e pode servir de base para o desenho de novos agentes antibiôticos. / It is well known that hemoglobin (Hb) is a source of biologically active peptides. The fragment 33-61 of bovine hemoglobin α-chain, isolated from the gut contents of the tick Boophilus microplus, was the first identified with antimicrobial activity . Its amidated analogue, Hb33-61a, showed to be active against Gram-positive bacteria and fungi strains [FogaÁa et al. (1999) J. Biol. Chem. 274, 25330-4]. The study of a series of carboxyl-free and amidated synthetic analogues of Hb33-61 revealed that C-terminus amidation enhances the activity against Candida albicans. Since Hb33-61a and Hb40-61a presented identical biological and structural properties, it seemed that Hb40-61a was Hb33-61a minimal active motif [SforÁa et al. (2005) Biochemistry 44, 6440- To test this suggestion, in the present study 51; Machado et al. (2007) Biopolymers 88, 413-26]. we synthesized, purified and characterized Hb40-61a analogues and assayed them against C. albicans and Micrococcus luteus. The results confirmed the suggestion only for the antifungal activity. When tested against fluconazole-resistant C. albicans, Hb40-61a was also active. Its antifungal activity showed to be dependent on the ionic strength of the medium. Its low hemolytic activity was confirmed even under low ionic strength conditions. Hb40-61a had no synergic effect with fluconazole on C. albicans. In vitro time-kill assays demonstrated that Hb40-61a kills the yeast rapidly. Therefore, this synthetic hemocidin may be of commercial interest for topical application or other uses involving low ionic strength medium. Moreover, it can serve as a template for the study of the mechanism of action of structurally related antimicrobial peptides or for the design of novel antibiotic drugs.

Leung Chung Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 142-146). / Abstracts in English and Chinese. / ABSTRACT (ENGISH) --- p.iii / ABSTRACT (CHINESS) --- p.v / ACHKNOWLEDGEMENTS --- p.vii / TABLE OF CONTENTS --- p.viii / Chapter CHAPTER 1 --- Introduction and Background / Chapter 1.1 --- Introduction of Platinum Drugs --- p.1 / Chapter 1.2 --- Mechanism of Action of Cisplatin --- p.3 / Chapter 1.3 --- Structure-Activity Relationships of the Platinum Drug 、 --- p.4 / Chapter 1.4 --- QS AR Parameters --- p.9 / Chapter 1.4.1 --- Chemical Hardness: Descriptor of Chemical Reactivity --- p.9 / Chapter 1.4.2 --- Possible Reaction Pathway of Platinum Drugs --- p.12 / Chapter 1.4.2.1 --- Proposed DNA Binding Pathway of Platinum Drugs --- p.13 / Chapter 1.4.2.1.1 --- Hydrolysis Pathway --- p.13 / Chapter 1.4.2.1.2 --- DNA Binding Pathway Involving the S-containing Biomolecules (Methionine Pathways) --- p.16 / Chapter 1.4.2.1.3 --- Conclusion --- p.21 / Chapter 1.5 --- Thesis Scope --- p.22 / Chapter CHAPTER 2 --- Theory and Methodology / Chapter 2.1 --- Introduction --- p.24 / Chapter 2.2 --- Density Functional Theory (DFT) --- p.24 / Chapter 2.2.1 --- Kohn-Sham Theorem --- p.25 / Chapter 2.2.2 --- Exchange-Correlation Energy Functional --- p.27 / Chapter 2.3 --- Basis Set --- p.27 / Chapter 2.3.1 --- Relativistic Effective Core Potential --- p.27 / Chapter 2.3.2 --- Double-Zeta --- p.28 / Chapter 2.3.3 --- Polarized Basis Set --- p.29 / Chapter 2.4 --- Solvation Model --- p.30 / Chapter 2.4.1 --- Continuum Model --- p.30 / Chapter 2.4.1.1 --- Simple Solvation Model --- p.31 / Chapter 2.4.1.1.1 --- Electrostatic Component --- p.31 / Chapter 2.4.1.1.2 --- Dispersion-Repulsion Interaction --- p.33 / Chapter 2.4.1.1.3 --- Cavitatoin Energy --- p.35 / Chapter 2.4.1.2 --- Polarized Continuum Model --- p.36 / Chapter 2.5 --- Methodology --- p.39 / Chapter 2.5.1 --- Calculation of DFT Global Reactivity Index --- p.39 / Chapter 2.5.1.1 --- Calculation for the Reaction Intermediates --- p.41 / Chapter 2.5.2 --- Calculation of the Reaction Pathways --- p.42 / Chapter CHAPTER 3 --- Results and Discussion / Chapter 3.1 --- Introduction --- p.49 / Chapter 3.2 --- Optimized Structure against Experimental Geometry --- p.49 / Chapter 3.3 --- Kohn-Sham Orbitals --- p.54 / Chapter 3.3.1 --- Location of the HOMO and LUMO --- p.55 / Chapter 3.4 --- Results of the DFT Reactivity Parameter --- p.57 / Chapter 3.5 --- Chemical Structure of the Drugs in the QSAR --- p.64 / Chapter 3.6 --- QSAR Analysis --- p.67 / Chapter 3.6.1 --- The Overall QSAR Plot of the Platinum Drugs --- p.68 / Chapter 3.6.1.1 --- Empirical Applicability of the QSAR on the Platinum(IV) Drugs --- p.70 / Chapter 3.6.1.2 --- Detail QASR Study According to the Type of Platinum Drug --- p.71 / Chapter 3.6.1.2.1 --- QSAR Study of the non-“trans-DACH´ح Platinum Drugs --- p.72 / Chapter 3.6.1.2.1.1 --- "QSAR Equation of the non-""trαns-DACH"" Platinum Drugs" --- p.75 / Chapter 3.6.1.2.2 --- QSAR Analysis for the Pt-trαns-DACH Drugs --- p.77 / Chapter 3.6.1.2.2.1 --- "QSAR Study of trans-S,S-DACH Platinum Drugs" --- p.79 / Chapter 3.6.1.2.2.2 --- "QSAR Study of trans-R,R-DACH Platinum Drugs" --- p.80 / Chapter 3.6.1.3 --- Summary --- p.81 / Chapter 3.7 --- QSAR Study of the Important Intermediates Using Chemical Hardness --- p.82 / Chapter 3.7.1 --- Optimized Structure for the Intermediates --- p.84 / Chapter 3.7.2 --- QSAR of the Dichloride Pt-Drugs Using Chemical Hardness of Parent Compounds --- p.90 / Chapter 3.7.3 --- QSAR of the Dichloride Pt-Drugs Using Chemical Hardness of Hydrolysis Intermediates --- p.91 / Chapter 3.7.4 --- QSAR of the Dichloride Pt-Drugs Using Chemical Hardness of Cyclic-Methionine Intermediates --- p.93 / Chapter 3.7.5 --- Conclusion --- p.95 / Chapter CHAPTER 4 --- Results and Discussion / Chapter 4.1 --- Introduction --- p.96 / Chapter 4.2 --- Study Scheme --- p.97 / Chapter 4.3 --- Optimized Structures --- p.98 / Chapter 4.4 --- Comments on the Reliability of the Calculation Model --- p.103 / Chapter 4.4.1 --- Reaction Profile in the Gas Phase --- p.104 / Chapter 4.4.2 --- Reaction Profiles Using Simple Solvation Model --- p.105 / Chapter 4.4.2.1 --- Defects of the Simple Solvation Model --- p.107 / Chapter 4.4.3 --- Reaction Profile Using PCM-UAHF Solvation Model --- p.109 / Chapter 4.4.3.1 --- Selection of the Reaction Parameters for the QSAR Study --- p.112 / Chapter 4.5 --- QSAR Study of Platinum Drugs Using the Reaction Parameters (AG and ΔG+) --- p.121 / Chapter 4.5.1 --- QSAR Analysis Using ΔG+(hydrolysis) --- p.121 / Chapter 4.5.2 --- QSAR Analysis Using ΔG(hydrolysis) --- p.123 / Chapter 4.5.3 --- QSAR Analysis Using ΔG+(guanine) --- p.125 / Chapter 4.5.4 --- QSAR Analysis Using ΔG(guanine) --- p.127 / Chapter 4.5.5 --- Further investigation of the Bidentate Pt-drugs DNA Binding --- p.129 / Chapter 4.5.5.1 --- Calculation Model --- p.129 / Chapter 4.5.5.2 --- Bidentate Pt-Drugs Reactions --- p.130 / Chapter 4.5.5.3 --- Selection of the Calculated Model for the QSAR Study --- p.133 / Chapter 4.5.5.4 --- QSAR Analysis Using ΔG+(guanine) for the Platinum Drugs with Bidentate Caboxylate Ligands --- p.136 / Chapter 4.5.5.5 --- QSAR Analysis Using ΔG(guanine) for the Platinum Drugs with Bidentate Carboxylate Ligands --- p.137 / Chapter 4.5.6 --- Conclusion --- p.138 / Chapter CHAPTER 5 --- Conclusion Remarks and Future Works / Chapter 5.1 --- Conclusion --- p.140 / Chapter 5.2 --- Future Works --- p.141 / REFERENCES --- p.142

Preparou-se, neste trabalho, nove cloridratos de N,N- [(dimetilamino)metil]benzamidas-p-X-substituidas em que X = N02, Br, Cl, I, F, H, CH3, OCH3 e N(CH3)2, SÉRIE II, ainda não descritos na literatura, a partir das respectivas bases, SÉRIE I. Os compostos obtidos foram identificados por seus espectros de I.V e RMN1H, e suas purezas determinadas por análise elementar e ponto de fusão. A seguir, determinou-se os valores de vC=O (cm-l ) em HCCl3, como medida de sua polaridade tanto para os compostos da SÉRIE I como para os da SÉRIE II. A aplicação da equação de HAMMETT, simples e expandida, aos valores obtidos forneceu excelentes correlações, verificando-se que os efeitos eletrônicos que os substituintes exercem sobre o grupo carbonila são de natureza indutiva e de ressonância, não havendo predominância de um sobre o outro. Determinou-se também, por bloqueio nervoso periférico em pata de rato, o grau de atividade anestésica local de sete dos nove compostos da SÉRIE II. A aplicação da equação de HANSCH aos valores de atividade anestésica local mostrou haver correlação razoável considerando-se os efeitos eletrônicos e hidrofóbicos exercidos pelos substituintes. A análise dos coeficientes de regressão obtidos sugere haver contribuição preponderante dos efeitos eletrônicos em relação à contribuição do efeito hidrofóbico para a atividade anestésica local. / In the present work nine N,N-[(dimethyl amino)methyl]benzamides-p-X-substituededs hydrochlorides (SERIES II) were prepared from the corresponding bases, (SERIES I), where X = N02, Br, Cl, I, F, H, CH3, OCH3 and N(CH3)3. The purity of the novel compounds, SERIES II, was established by elemental analysis. The recorded infrared and 1HNMR spectra were in agreement with their structures. For both sets of compounds the carbonyl group infrared frequencies in HCCl3 were determined and used as measurement of the polarity of the group. The obtained vC=O (cm-1) values showed excellent correlations when a simple or a multiparameter HAMMETT equation was applied. This suggests that the eletronic effect of the substituents on the carbonyl stretching frequencies is of inductive and ressonanee nature, without predominances of one over the other. Were also determined by peripheryc nervous blockade on rats paw, the degree of local anesthetic activity on seven of the nine compounds of SERIES II. The application of the HANSCH equation to the local anesthetie activity values showed reasonable correlation when the eletronic and hydrophobic effects of the substituents were considered. Analysis of the obtained regression coefficents suggest that the contribution of the former effect to the local anesthetic activity predominants.

A reemergência de algumas bactérias Gram-positivas, em particular, do gênero Staphylococcus, como principal foco causador de infecções hospitalares, tem se intensificado nas últimas décadas, e, apesar da existência de potentes fármacos voltados para o tratamento de infecções causadas por este gênero de bactéria, as taxas de morbidade e mortalidade prevalecem com perfil crescente. Além disso, um grande problema associado a cepas de MRSA (Methicillin-Resistant Staphylococcus aureus) é o fenótipo de multi-resistência, característica que confere a este microrganismo resistência não apenas à meticilina como também a uma série de outros fármacos, exceto frente à vancomicina e à teicoplanina. Muito tem se feito, mas ainda são poucos os resultados efetivamente aplicáveis no tratamento de infecções com caráter de multi-resistência, justificando, desta forma, a necessidade de desenvolvimento de sucedâneos que sejam consideravelmente mais efetivos para a solução deste problema. Baseado nestes fatos, a proposta deste estudo envolveu o planejamento, síntese, identificação e estudos de QSAR (Quantitative Structure-Activity Relationships) em duas e três dimensões de derivados 5-nitro-2-tiofilidênicos com atividade antimicrobiana frente a cepas padrão e multi-resistente de Staphylococcus aureus. A escolha dos grupos substituintes foi realizada em duas etapas. Na primeira delas seguiu-se metodologia de substituição em anéis aromáticos proposta por Topliss para a otimização da bioatividade de compostos. Em uma segunda etapa, predominantemente quantitativa, foram selecionados mais alguns derivados baseando-se em faixa de hidrofobicidade ótima pré-determinada experimentalmente e na variação de efeito estérico dos grupos substituintes. Quatorze derivados 5-nitro-2-tiofilidênicos foram sintetizados, estruturalmente identificados e avaliados quanto à atividade antimicrobiana frente às cepas padrão (ATCC 25923) e multi-resistente (3SP/R33) de Staphylococcus aureus por determinação da concentração inibitória mínima empregando-se método de macrodiluição sucessiva em tubos. Salienta-se que a cepa 3SP/R33 se mostra resistente a dezenove antibióticos empregados na prática médica e apresenta suscetibilidade apenas à vancomicina. As concentrações inibitória e bactericida mínimas apresentadas pelos compostos sintetizados mostraram sofrer influência significativa da hidrofobicidade sobre as referidas atividades de acordo com os estudos de QSAR-2D e QSAR-3D, sendo os resultados obtidos para a cepa multi-resistente absolutamente compatíveis com os anteriormente determinados para a cepa padrão. Os estudos de QSAR-2D indicaram que a atividade antimicrobiana das 5nitro-2-tiofilideno benzidrazidas substituídas sofre influência significativa de duas propriedades físico-químicas que são a hidrofobicidade e a distribuição eletrônica. A relevância dos descritores estruturais σ e efe na determinação da atividade antimicrobiana, sinalizam que a distribuição eletrônica influencia fortemente o aumento da potência antimicrobiana dos compostos em estudo tanto pela influência dos efeitos indutivo e de ressonância na estrutura química do ligante, como também pelos campos moleculares gerados ao redor de grupos substituintes, sugerindo uma possível interação dos mesmos com uma área específica do sítio receptor. Nos estudos de QSAR-3D, foi evidenciado, em concordância com o estudo clássico anteriormente realizado, que a hidrofobicidade prevalece como propriedade de fundamental importância no estabelecimento da atividade antimicrobiana. Foi observada a importância da presença de regiões hidrofílicas pontuais nos compostos de forma a propiciar processos de solvatação e dessolvatação que são críticos na difusão através de membranas biológicas. Pode-se afirmar que a análise de QSAR, considerando os aspectos tridimensionais ligantes, ressaltou a necessidade de um balanço lipofílico-hidrofílico para um bom desempenho das 5-nitro-2-tiofilideno benzidrazidas ρ-substituídas como agentes antimicrobianos. A partir dos resultados obtidos evidenciou-se, neste estudo, o forte potencial de derivados 5-nitro-2-tiofilidênicos como possível alternativa para o desenvolvimento racional, em nível molecular, de fármacos voltados para o tratamento de infecções causadas por cepas multi-resistentes de Staphylococcus aureus. / In the last decade, there has been a reemergence of Gram-positive bacteria, in particular Staphylococcus, which isconsidered one of the. most causing of nosocomial infections. Although potent antistaphylococcal drugs are available, this infection continues presenting increasing morbidity and mortality rates. Besides, a serious problem associated with MRSA (Methicillin-Resistant Staphylococcus aureus) is the phenotype of multidrug resistance, which is, resistance not only to methicillin but also to many other drugs, except to vancomycin and teicoplanin. Many efforts have been made in a tentative to reduce this problem, nevertheless there is only a few number of alternatives to combat Staphylococcus aureus multidrug-resistant strains, justifying the necessity of development of more effective compounds to the treatment of these infections. Based in these facts, the purpose of this study was the design, synthesis, structural identification and 2D-QSAR and 3D-QSAR (Quantitative Structure-Activity Relationships) studies of 5-nitro-2-thiophylidene derivatives with antimicrobial activity against multidrug-resistant strains of Staphylococcus aureus. The choice of substituent groups was made in two stages. The first stage comprises on application of Topliss operational scheme for aromatic substitution. In a second quantitative stage, more derivatives were selected according by hydrophobicity range previously determined. Other standard considered at the selection of substituent groups was the variation of steric effect. Fourteen 5-nitro-2-thiophylidene derivatives were synthesized, structural identified and tested against standard (A TCC 25923) and multidrug-resistant (3SP/R33) strains of Staphylococcus aureus. The Minimal Inhibitory Concentration, MIC, was determined using the serial dilution tests in two sequential stages. The 3SP/R33 strain is resistant to nineteen antimicrobial agents in use, except to vancomycin. The minimal inhibitory and bactericidal concentrations of synthesized compounds showed, according by 2D-QSAR and 3D-QSAR studies, a significant influence of hydrophobic properties on antimicrobial activity determination and the results obtained for multidrug-resistant strain were consistent with those determined for A TCC 25923 strain. 2D-QSAR studies showed that antimicrobial activity are mainly influenced by two physico-chemical properties: hydrophobicity and electronic distribution. The relevance of σ e ephe parameters on antimicrobial activity determination, denotes the contribution of inductive and resonance effects for the polar performed by the substituent groups, probably suggesting an interaction between them and specific receptor site. 3D-QSAR studies showed that hydrophobicity is a essential property to antimicrobial activity determination, sustained the same conclusions previously obtained by Hansch Analysis. It was observed a great concern of small hydrophilic regions distributed on derivatives in order to promote solvation and desolvation process, that have critical importance on diffusion process through the biological membranes. QSAR studies considering three-dimensional properties of ligands indicated the necessity of accurate hydrophilic-hydrophobic balance on nitrothiophene derivatives for their good performance as antimicrobial agents. The results obtained in this preliminary study have shown the potential of synthesized compounds as alternatives to the treatment of infections caused by multidrug-resistant strains of Staphylococcus aureus.

Submitted by Rosangela Silva (rosangela.silva3@unioeste.br) on 2017-08-30T20:10:51Z No. of bitstreams: 2 TAISA PEREIRA PIACENTINI RIBEIRO.pdf: 3904493 bytes, checksum: 479855c30863d881e3a40de6b85ca548 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-08-30T20:10:51Z (GMT). No. of bitstreams: 2 TAISA PEREIRA PIACENTINI RIBEIRO.pdf: 3904493 bytes, checksum: 479855c30863d881e3a40de6b85ca548 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-09 / The search for new herbicides to control herbicides-resistant weeds is necessary to attend the rising demand of food from the world’s population. This work was divided into two parts. The first aimed to obtain a model of QSAR-2D, 3D and hybrid to predict compounds with activity to the inhibition of photosynthesis. For this, was used a data set of 44 quinoline analogues described in the literature as PET inhibitors, and all tested in the same bioassay method. For construction of models were used the programs QSAR Modeling and Pentacle. The obtained models A, C and D, were approved in the validation tests (internal and external), they are robust and with good predictive capacity. The second part of studie aimed to identify a pharmacophore model, for select compounds from the data set of first part, aiming to use as a tool for virtual screening. The research resulted in 86,560 compounds, and thus several screening filters were applied according to Briggs rule of three, in silico toxicity analyzes, unsupervised pattern recognition (PCA), and docking studies. As a result, 28 compounds remained, all of which showed potential to be herbicides, through the prediction using the obtained QSAR models, however, only the model D proved to be reliable for prediction the virtual screening. Finally, we selected the ten compounds that presented the highest predictive value of PET inhibition activity, using the model D. / A busca de novos herbicidas para o controle de ervas daninhas resistentes é necessária para atender à crescente demanda alimentar da população mundial. Este trabalho foi dividido em duas partes. A primeira teve por objetivo a obtenção de modelos de QSAR-2D, 3D e híbrido para previsão de compostos com atividade de inibição da fotossíntese. Para isso, foi utilizado um conjunto de dados formado por 44 análogos de quinolina descritos na literatura como inibidores do PET e todos testados pela mesma metodologia de ensaio biológico. Para construção dos modelos foram utilizados os programas QSAR Modeling e Pentacle. Os modelos A, C e D obtidos foram aprovados nos testes de validação (interna e externa), são robustos e com boa capacidade de previsão. A segunda parte do estudo teve como objetivo a identificação de um modelo farmacofórico, para compostos selecionados do conjunto de dados da primeira parte, visando o uso do mesmo como ferramenta para triagem virtual. A pesquisa resultou em 86.560 compostos, e assim foram aplicados diversos filtros de seleção de acordo com a regra de três de Briggs, análises “in silico” de toxicidade, técnica de reconhecimento de padrões não supervisionados (PCA), e estudos e ancoramento molecular. Como resultado, restaram 28 compostos, sendo que todos mostraram potencial para serem herbicidas, através da previsão utilizando os modelos de QSAR obtidos, porém apenas o modelo D mostrou-se confiável para previsão da triagem virtual. Por fim, foram selecionados os dez compostos que apresentaram maior valor de previsão de atividade de inibição do PET, utilizando o modelo D.