The importance of the searching for novel antimycobacterial active agents is continually increasing with growing mycobacterial resistance to currently used drugs. However, the resistance-related problems are also associated with other bacteria and fungi. The systematic modification of compounds with a known antimicrobial activity represents one of the possible approaches to overcome this problem. Sulphonamide derivatives may be considered to be such a kind of compounds. That is why we synthesized various sulphathiazole derivatives. Amides were obtained by the reaction of sulphathiazole with appropriate acyl chlorides, substituted ureas from corresponding isocyanates. These ureas were cyclized via oxalyl chloride to form substituted 2,4,5-trioxoimidazolidines. Among derivatives evaluated for their antimycobacterial action, 4-(3- phenethylureido)-N-(thiazol-2-yl)benzenesulphonamide showed the highest activity. Its minimum inhibitory concentrations (MIC) against Mycobacterium tuberculosis My 331/88 (4 µmol/l) were superior to those obtained for sulphathiazole. In the case of nontuberculous mycobacteria (M. avium My 330/88, M. kansasii My 235/88 and M. kansasii My 6509/96), their activities were comparable (≥ 2 µmol/l). Amides showed also a significant antimycobacterial activity, especially against M....

Thesis (M.Sc. (Chemistry)) -- University of Limpopo, 2020 / In an attempt to synthesise quinoxaline-ferrocene compounds with antimycobacterial activity; a series of quinoxaline alkynyl derivatives were successfully synthesised from 3- (quinoxalin-3-yl)prop-2-yn-1-ol 86A and 3-(6-chloroquinoxalin-2-yl)prop-2-yn-1-ol 86B. In this series compounds 87A – B, 90A – B, and 93A – C were intermediates obtained in an effort to synthesise quinoxaline-ferrocene compounds. Treatment of either 86A or 86B with various acid chlorides afforded quinoxaline alkynyl ester derivatives 97A - 97B. Within this series, two quinoxaline-ferrocene compounds 3-(quinoxalin-3-yl)prop-2-ynyl ferrocetate 97A-iv and 3-(6-chloroquinoxalin-2-yl)prop-2-ynyl ferrocetate 97B-iv were successfully incorporated with ferrocenoyl chloride and obtained in 42 - 43% yield. The reactions of 3-chloroquinoxaline-2-carbonyl chloride 99 with ferrocenyl alcohol and ferrocenyl amine were unsuccessful. However, 3-chloroquinoxaline-2-carbonyl ester 100A - C and amide 101A - D derivatives with various alcohols and amines were obtained. The structures of all the compounds were confirmed by spectroscopic analysis (NMR, FT-IR and HRMS). The synthesised compounds were all evaluated for preliminary in-vitro antimycobacterial activity. The results obtained exhibited compound 90B with the highest activity against Mtb H37RV strain at MIC90 of 1.13 µM, followed by 90A and 87A exhibiting MIC90 of 4.55 and 6.47 µM, respectively. The quinoxaline alkynyl ester derivatives were found to exhibit poor to good activity. Within this series, three compounds were found to exhibit antimycobacterial activity at MIC90 ˂ 20 µM with compound 97A-ii showing the highest activity at MIC90 of 16.18 µM, followed by 97A-i and 97B-iii showing MIC90 of 18.05 and 19.36 µM, respectively. From the two quixonaline-ferrocene compounds, compound 97A iv was found to exhibit antimycobacterial activity at MIC90 of 39.90 µM. However, compound 97B-iv was found to be inactive. The 3-chloroquinoxaline-2-carbonyl ester 100A - C and amide 101A - D derivatives were found to be inactive. However, compound 99-C was found to exhibit antimycobacterial activity at MIC90 of 40.66 µM. Compounds 86A, 86C, 87A and 90A were evaluated for in-vitro antiproliferative activity against cancer cell lines. The results of antiproliferative activity showed that compounds 86A and 87A exhibited excellent activity against A549 lung cancer cell lines. Compound 87A was found to be the most active against A549 cell line showing 50% viability-inhibition at 25 µM / National Research Foundation (NRF)

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No. of bitstreams: 1 Tese - Daiane Martins.pdf: 4237333 bytes, checksum: e9cd7f69803566a70db4c62a6e1bb668 (MD5) Previous issue date: 2014-02-25 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / The species of Rubiaceae revealed great diversity of secondary metabolites, which are responsible for a range of biological activities. Among these species is Duroia macrophylla Huber, endemic to the Amazon Rainforest, popularly known as “cabeça-de-urubú, apuruí ou puruí-grande-da-mata”. The absence of studies of plants of the genus Duroia and the absence of chemical studies and biological activity to D. macrophylla, the aim of this work was to isolate the chemical constituents and evaluate the extracts and compounds isolated on activities: antioxidant, toxicity against Artemia salina, antibacterial, antimycobacterial and antitumor. The plant material was collected two times, dried, grounded and extracted with dichloromethane or hexane and methanol. The extracts were subjected to phytochemical screening by comparative thin layer chromatography and to determine specific telltale signs of chemical classes. The extracts were tested as antioxidant, cytotoxic, antibacterial, antimycobacterial and antitumor, to increase the chances of obtaining active molecules and/or prototypes of drugs. The isolated compounds were identified by spectroscopic methods (1H, 13C and two-dimensional NMR) and mass spectrometry and essayed as antimicrobial and antitumor. All extracts showed signs of terpenes and only the dichloromethane extracts of leaves and branches of the 1st collection did not reveal with DPPH. The methanol extracts of both collections showed aromatic compounds. The presence of alkaloids was detected only in extracts from the branches of the 2nd collection. There were isolated and identified four substances of the extracts of the 1st collection: two triterpenes from dichloromethane extract of the leaves (oleanolic acid and ursolic acid), one chalcone from methanol extract of the leaves (4,4'- dihydroxy-3'-chalcone) and a phenolic acid from methanol extract of the branches (mmethoxy- p-hydroxy-benzoic acid). Were identified of the extracts of the 2nd collection, eight monoterpene indole alkaloids: 10-methoxy-ajmalicine, 11-methoxy-ajmalicine, 11-methoxy- 3-isoajmalicine, 9-methoxy-3-isoajmalicine, 9-methoxy-19-epi-3-isoajmalicine, 10-methoxy- 19-epi-3-isoajmalicine, 10-methoxy-3-isorauniticine and 10-methoxy-rauniticine. All compounds isolated in this study were described for the first time in the genus Duroia. The methanol extracts from leaves and branches in both collections showed a good antioxidant activity. In cytotoxic assay against A. salina only the methanol extract of the leaves (2nd collection) presented toxicity at lethal concentration (LC50) of 120 mg/mL. The extracts showed bacteriostatic activity against the bacteria Klebsiella pneumoniae, Flavobacterium corumnare, Salmonella enteridis and Pseudomonas aeruginosa. Of the substances tested only oleanolic acid showed antibacterial activity against Nocardia brasiliensis and Serratia marcescens, with a MIC of 500 mg/mL. Extracts subjected to antimycobacterial bioassay, the dichloromethane extract of the leaves (1st collection) showed better results against all strains of Mycobacterium tuberculosis with an MIC of 6.25 mg/mL for INHr strain, 25 mg/mL for the strain RMPr and ≤ 6.25 mg/ml for H37Rv strain. Only the alkaloids 10-methoxy-3- isorauniticine, the mixture of 9-methoxy-3-isoajmalicine with 9-methoxy-19-epi-3- isoajmalicine, 10-methoxy-3-isorauniticine and 10-methoxy-rauniticine tested against M. tuberculosis (strain INHr) showed better results rather those obtained from crude extracts. The extracts and alkaloids showed low cytotoxic potential on neoplastic cell lines: HCT116 (human colorectal carcinoma), MCF-7 (breast carcinoma), SK -Mel-19 (human melanoma) and on the non-neoplastic line: MRC-5 (human lung fibroblast). Keywords: alkaloids, antioxidant activity, antimycobacterial activity. / As espécies pertencentes à família Rubiaceae revelaram grande diversidade de metabólitos secundários, os quais são responsáveis por uma gama de atividades biológicas. Entre estas espécies encontra-se Duroia macrophylla Huber, endêmica da Floresta Amazônica, conhecida popularmente como cabeça-de-urubú, apuruí ou puruí-grande-da-mata. A escassez de estudos de plantas do gênero Duroia e a ausência de estudos químicos e de atividade biológica para D. macrophylla, instigaram este trabalho, cujo o objetivo foi isolar os constituintes químicos e avaliar os extratos e substâncias isoladas quanto às atividades: antioxidante, toxicidade frente à Artemia salina, antibacteriana, antimicobacteriana e antitumoral. Foram realizadas duas coletas desta espécie, extraída com diclorometano (DCM) ou hexano (Hex) e metanol (MeOH). Os extratos foram testados como antioxidante, citotóxico, antibacteriano, antimicobacteriano e antitumoral, com intuito de ampliar as chances de obter moléculas ativas e/ou protótipos de fármacos. As substâncias isoladas foram identificadas por métodos espectroscópicos (RMN de 1H, de 13C e bidimensionais) e por espectrometria de massas e testadas como antimicobacteriana e antitumoral. Na prospecção fitoquimica todos os extratos apresentaram indícios de terpenos e apenas os extratos DCM de folhas e galhos da 1ª coleta não apresentaram capacidade antioxidante frente ao revelador DPPH. Os extratos MeOH de ambas as coletas apresentam compostos aromáticos. A presença de alcaloides foi detectada apenas nos extratos dos galhos da 2ª coleta. Foram isoladas e identificadas quatro substâncias dos extratos da 1ª coleta: dois triterpenos do extrato DCM das folhas (ácido oleanólico e ácido ursólico), uma chalcona do extrato MeOH das folhas (4,4’dihidroxi-3’-chalcona) e um ácido fenólico do extrato MeOH dos galhos (ácido m-metoxi-p-hidroxi-benzoico). Dos extratos da 2ª coleta foram identificados oito alcaloides indólicos monoterpênicos: 10-metoxi-ajmalicina, 11-metoxi-ajmalicina, 11-metoxi-3-isoajmalicina, 9-metoxi-19-epi-3-isoajmalicina, 9-metoxi- 3-isoajmalicina, 10-metoxi-19-epi-3-isoajmalicina, 10-metoxi-3-isorauniticina e 10-metoxirauniticina. Todas as substâncias isoladas neste estudo estão sendo descritas pela primeira vez no gênero Duroia. A atividade antioxidante dos extratos MeOH de folhas e galhos de ambas as coletas foi bastante significativa. No ensaio citotóxico frente A. salina apenas o extrato metanólico das folhas da 2ª coleta apresentou toxidade na concentração letal (CL50) de 120 μg/mL. Os extratos apresentaram atividade bacteriostática sobre as bactérias Klebsiella pneumoniae, Flavobacterium corumnare, Salmonella enteridis e Pseudomonas aeroginosa. Das substâncias testadas apenas o ácido oleanólico apresentou atividade antibacteriana frente à Nocardia brasiliensis e Serratia marcescens, com uma CIM de 500 μg/mL. Dos extratos submetidos ao bioensaio antimicobacteriano, o extrato DCM das folhas (1ª coleta) apresentou melhor resultado frente às três cepas de Mycobacterium tuberculosis, com uma CMI de 6,25 μg/mL para a cepa INHr, de 25 μg/mL para a cepa RMPr e ≤ 6,25 μg/mL para a cepa H37Rv. Os alcaloides 10-metoxi-ajmalicina, a mistura de 9-metoxi-3-isoajmalicina com 9-metoxi-19- epi-3-isoajmalicina, 10-metoxi-3-isorauniticina e 10-metoxi-19-epi-3-isoajmalicina foram ativos frente ao M. tuberculosis (cepa INHr). Os extratos e alcaloides apresentaram baixo potencial citotóxico sobre as linhagens de células neoplásicas: HCT116 (carcinoma colorretal humano), MCF-7 (carcinoma de mama), SK-Mel-19 (melanoma humano) e sobre a linhagem não neoplásica: MRC-5 (fibroblasto de pulmão humano).

Chemotherapy of tuberculosis (TB), a disease caused by Mycobacterium tuberculosis (M. tuberculosis), is successful against actively-growing bacilli but ineffective against dormant/persistent organisms, found mainly in a protective lipid-laden granuloma, possibly necessitating the use of lipophilic antibiotics. In vitro, these bacilli are encased in lipid-rich biofilms. In this study, the antimycobacterial activity of one such agent, clofazimine, and its nanoparticle formulation, have been investigated against Mycobacterium smegmatis (M. smegmatis), as a surrogate for M. tuberculosis, by determining the bacteriostatic and bactericidal activities of the native (NC) and spray-dried (SDC) preparations of this agent on planktonic and biofilm populations, as well as their effects on biofilm formation and its lipid compositions, specifically free mycolic acid (FM) content. Both preparations were comparable, being bacteriostatic for rapidly-proliferating bacilli, bactericidal for slow-growing, biofilm-producing sessile bacteria, but ineffective against non-replicating, biofilm-encased M. smegmatis organisms. However, similar studies in M. tuberculosis are required. / Dissertation (MSc)--University of Pretoria, 2013. / Immunology / Unrestricted

Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Chemistry and Pharmaceutical Analysis Author: Cristina Paredes de la Red Supervisor: prof. PharmDr. Martin Doležal, Ph.D. Title of diploma thesis: Synthesis and antiinfective evaluation of substituted N-(pyrazine-2- yl)benzenesulfonamide Tuberculosis (TB) is among the ten leading causes of death, especially in developing countries. Even though it is an old disease with established treatment regimen, there has been an increased resistance to anti-TB drugs 1 . The anti-tubercular pyrazinamide has caught the attention of researchers as the different theories for its mechanism of action have made it an interesting entity for further investigation. Here we will discuss N-(pyrazine-2-yl)benzenesulfonamides (General structure is presented in the Figure below) as a new derivatization approach based on synergism methodology between pyrazinamide and sulfonamides. Sulfonamides exert their antimicrobial effect by competitive inhibition of folic acid synthesis and subsequent inhibition of bacterial growth and reproduction 18 . I have contributed to the synthesis and purification of 8 compounds in a series of total 22 N- pyrazinylsulfonamides. Two of the prepared compounds showed activity against Mycobacterium kansasii [2a (MIC...

Thesis (MSc. (Microbiology)) -- University of Limpopo, 2019 / The emergence of drug resistance to the first line drugs complicates the treatment of tuberculosis (TB), especially in parts of sub-Saharan Africa where accessibility to quality health care is limited. The search for alternative medication has been the centre of research for years due to challenges posed by infectious organisms including drug resistance, lengthy treatment periods and lack of quality health care in developing countries. Stomatostemma monteiroae is used in traditional medicine to treat TB and related symptoms. The aim of this study was to isolate and characterise compounds with antimycobacterial activity from Stomatostemma monteiroae. The plant materials were collected from Ga-Madiga village in Limpopo province of South Africa. Different plant parts namely: leaves, twigs, roots, tuber and tuber-peels were separated, washed, dried and milled to a fine powder. Several solvents (n-hexane, dichloromethane, acetone and methanol) were used to extract the plant material using various extraction methods such as maceration, defatting, and extract enrichment procedure and phytochemical analysis was done using standard chemical tests and thin layer chromatography. The qualitative antioxidant activity was determined by the thin layer chromatography (TLC) based 2,2-diphenyl-1picrylhydrazyl (DPPH) free radical scavenging activity and quantitative antioxidant activity was determined using colorimetric DPPH free radical scavenging and ferric reducing power assay. Antimycobacterial activity of the extracts was assessed using bioautography and micro dilution method tested on Mycobacterium smegmatis (ATCC 1441), Mycobacterium tuberculosis (ATCC 25177) and M. tuberculosis H37Rv (ATCC 27294). The cytotoxic effects of the extracts were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on Vero monkey kidney cells. The compounds with antimycobacterial activity were isolated using bioassay-guided fractionation and purified using preparative thin layer chromatography and thereafter identified using NMR spectroscopy to elucidate the structure. Various phytochemical constituents were detected in different plant parts, with the leaves and twigs possessing more of the phytoconstituents analysed. The TLC profile of S. monteiroae indicated that more compounds are non-polar to intermediate in polarity. The antioxidant activity analysis on TLC plates indicated that all the plant parts have low antioxidant activity, this was also confirmed by xxii quantitative tests. The leaves of S. monteiroae had antimycobacterial activity when analysed using bioautography, while other plant parts had no active bands. The minimum inhibitory concentration values were much higher than the positive control rifampicin and the roots (0.31 mg/mL) followed by the leaves (0.83 mg/mL) had lower inhibitory concentrations when tested against M. smegmatis. The MIC values of extracts against TB causing strains varied greatly, the leaves and the roots had even higher MIC value. Toxicity analysis indicated that all plant parts were non-toxic towards Vero cells (LC50 > 0.02 mg/mL). Bioassay-guided fractionation enabled isolation of one antimycobacterial pure compound from the leaves extracts. The isolated compound was identified using NMR and was found to be a sitosterol derivative 8,9-dehydro-4-methyl-24-vinylobtusifoliol. This compound had a noteworthy activity against M. smegmatis. The present study validates the use of S. monteiroae in the treatment of TB related symptoms traditionally. Further studies are required to analyse the cytotoxic effects of the isolated compound and also testing the antimycobacterial activity of the isolated compound on TB causing pathogens. / National Research Foundation (NRF)

Main goal of this Ph.D. thesis is to develop voltammetric methods for the electrochemical study of novel antimycobacterial compounds hydroxynaphthalene- carboxamides. Firstly, this study was focused on the miniaturization of voltammetric methods and construction of an electrochemical microcell due to usually small volume of samples that are associated with an analysis of biologically active compounds in biological matrices. Therefore, all aspects of the voltammetric procedure were studied in a relation to miniaturization. Microcells were based on commercially available electrodes: glassy carbon electrode as a reliable electrode material with well-described characteristics and a novel silver solid amalgam electrode. This study was carried out with analytes 4-nitrophenol, pesticide difenzoquat, and 1-hydroxy-N-(4-nitrophenyl)naphthalene-2-carboxamide. Attention was paid especially to the optimization of oxygen removal procedures in the drop of a solution. Developed miniaturized methods had the same parameters for the determination of studied compounds as in bigger volumes. The proposed electrochemical microcell can be generally used for voltammetric analysis of those samples of biological or environmental origin that are usually available in very limited volumes. Second part of the thesis was focused...