Thesis (M.Sc. (Microbiology)) --University of Limpopo, 2011 / The leaves of fifteen plant species were collected from the Lowveld Botanical Garden in Nelspruit, Mpumalanga Province, South Africa. The collection was based on a list of plants and their ethnopharmacological information provided by the Phytomedicine Programme at the University of Pretoria. The dried leaves of the plants were powdered and extracted using hexane, dichloromethane, acetone and methanol. The extracts were screened for antibacterial activity against Mycobacterium smegmatis and Rhodococcus erythropolis. The acetone extract of Milletia stulhimannii was the most active, showing activity against Mycobacterium smegmatis and Rhodococcus erythropolis with MIC values 0.13 and 0.08 mg/ml, respectively. Acetone extracts for all plants had the lowest MIC values ranging between 0.11-1.25 mg/ml and 0.08-1.25 mg/ml for M. smegmatis and R. erythropolis, respectively. Milletia stulhimannii, Albizia gummifera, Xanthocercis zambesiaca and Barringtonia racemosa extracts have shown the greatest potential for anti-tubercolosis agents. These were all active against M. smegmatis with an average MIC value of acetone extracts of 0.13 mg/ml. Apodytes dimidiata was selected for the isolation of active compounds since its activity on qualitative antibacterial activity assays was highly prominent on TLC plates in comparison to the other plant extracts. Two compounds were isolated from A. dimidiata but after purification, their MICs were above 2.5 mg/ml indicating a possible loss of activity during purification. The preliminary NMR spectra analysis suggested that the compounds were a long fatty acid and a triterpene. Future work is required to elucidate the chemical structures of the latter compounds and to test the activity of these compounds against Mycobacterium tuberculosis. / Department of Water Affairs, and University of Limpopo Research Development and Administration Office

Thesis (M.Sc. (Agriculture)) --University of Limpopo, 2006 / Refer to document / National Research Foundation (NRF) and Cannon Collins Educational Trust Fund of Southern Africa (CCETSA)

Orientador: Ary Fernandes Júnior / Resumo: A busca por novos fármacos é uma constante, especialmente para aqueles obtidos a partir de produtos naturais, que apresentem melhor eficácia e vários efeitos terapêuticos. A própolis e o veneno (apitoxina) da abelha Apis mellifera, além da melitina, uma fração da apitoxina, possuem ação antimicrobiana reportada na literatura. As ações antibacterianas do extrato hidroalcoólico de própolis (EHP), de apitoxinas obtidas das abelhas Apis mellifera submetidas a floras apícolas diferentes (Api 1 - flora apícola silvestre, Api 2 - flora apícola de eucalipto, Api 3 - flora apícola de laranjeira, Api 4 - flora apícola silvestre associada com alimentação artificial) e de melitina foram testadas sobre isolados clínicos de Staphylococcus aureus resistentes à meticilina (MRSA) utilizando metodologia da microdiluição (Resazurin Microtiter Assay Plate – REMA) para obtenção dos respectivos valores de concentração inibitória mínima (CIM) e concentração bactericida mínima (CBM). Ensaios também foram realizados para verificação de sinergismo entre o EHP, as diferentes apitoxinas e a melitina em combinação com a oxacilina sobre uma linhagem de MRSA ATCC e um isolado clínico de MRSA utilizando metodologia da curva de sobrevivência (time kill curve). Foram realizados ensaios inéditos objetivando verificar também se a Api 1 e melitina inibem a produção de enterotoxinas sobre cepas ATCC de S. aureus SEA, SEB, SEC, SED e se inibem a produção de biofilme sobre a cepa ATCC de S. aureus. A microscopia el... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Microbe resistence is a serious issue, especially as they have become resistant to most well known drugs. Therefore this is considered as a global problem and is now dealt with at a poitical level. Since no new classes of antimicrobial agents have been discovered in the past three deacdes, the development of new drugs is extremely urgent. Therefore the aim of this project was to synthesise derivatives of benzimidazole, and then assesses their antimicrobial activities in vitro by using disc (well) diffusion and MICs tests. A total of 69 benzimidazole derivatives, with substituents at positions 1, 2, and 5, were synthesised, characterised and tested against selected bacteria and fungi. In addition, six bezimidazole silver complexes were prepared and evaluated for their antimicrobial behavior. The SAR showed that the antimicrobial activity of the compounds depended on the substituents attached to the bicyclic heterocycle. Some promising results were obtained. In particular, 5 compounds displayed antibacterial activity against two MRSA strains with MIC values corresponding to ciprofloxacin, which can be considered significant. The compounds have some common features; four possess 5-chloro or 5-bromo substituents; two are derivatives of (S)-2- ethanaminebenzimidazole and the others are derivative of one 2-(chloromethyl)-1Hbenzo[d]imidazole, (1H-benzo[d]imidazol-2-yl)methanethiol and 2-(methoxymethyl)-1-methyl-1H-benzo[d]imidazole. The results from the antifungal screening were very interesting as there were 26 compounds, including two silver complexes, which were potent fungicides against the selected fungal species. They showed equivalent or greater potentency in their MIC values than amphotericin B. In particular, the 5-fluoro, 5-chloro and 5-bromo benzimidazole showed broad spectrum activity.

Publics are facing a great challenge of infections from pathogens. Polyethylene terephthalate (PET) is widely used in health-care settings. It is vital to develop effective and regenerable antimicrobial PET. In this study, effective antibacterial modification of PET was achieved by immobilizing N-halamine biocide poly (N-chloroacrylamide) (PCA) onto PET through the formation of a surface interpenetrating network. The successful and uniform immobilization was confirmed by FTIR and XPS. The immobilization is durable to a 72 hours soxhlet extraction. Surface morphology of the fabrics did not significantly change after modification with IP less than 20%. The modified fabric can bring 100% reduction of 10e6 CFU/ml of several clinical important bacteria in 15 min contact. The regenerability of N-halamine on PAM modified PET was studied by FTIR, titration and N analysis. After 30 regeneration cycles, the PAM-DVB network modified PET was still able to provide 100% reduction of HA-MRSA in 20 min contact.

Publics are facing a great challenge of infections from pathogens. Polyethylene terephthalate (PET) is widely used in health-care settings. It is vital to develop effective and regenerable antimicrobial PET. In this study, effective antibacterial modification of PET was achieved by immobilizing N-halamine biocide poly (N-chloroacrylamide) (PCA) onto PET through the formation of a surface interpenetrating network. The successful and uniform immobilization was confirmed by FTIR and XPS. The immobilization is durable to a 72 hours soxhlet extraction. Surface morphology of the fabrics did not significantly change after modification with IP less than 20%. The modified fabric can bring 100% reduction of 10e6 CFU/ml of several clinical important bacteria in 15 min contact. The regenerability of N-halamine on PAM modified PET was studied by FTIR, titration and N analysis. After 30 regeneration cycles, the PAM-DVB network modified PET was still able to provide 100% reduction of HA-MRSA in 20 min contact.

Klinikinėje praktikoje infekcinėms ligoms gydyti vartojama daugiau kaip 200 priešmikrobinių medžiagų, tačiau infekcinės ligos yra viena dažniausių mirties priežasčių ir naujų priešmikrobinių vaistų poreikis nemažėja. Modifikuojant 4-tiazolidinono žiedą susintetinami įvairaus biologinio aktyvumo junginiai. 4-tiazolidinono dariniai su sulfanilamido farmakoforu yra aktyvesni už sulfanilamidus prieš bakterijas ir pasižymi priešgrybeliniu poveikiu; su nitrofurano farmakoforu yra vieni aktyviausių priešmikrobinių junginių. Alilaminą įjungus į molekulę kartu su jau anksčiau žinomais farmakoforais, tikėtąsi geresnio naujų junginių priešmikrobinio aktyvumo. Pritaikius pasirinktas metodikas naujų 4-tiazolidinono darinių su pasirinktų farmakoforų (sulfanilamido, nitrofurano, alilamino) struktūriniais fragmentais sintezei, susintetinti 39 4-tiazolidinono ciklą turintys junginiai. Įvertinus fiziko-chemines savybes ir toksiškumo riziką in silico, nustatyta junginių, kaip biologiškai aktyvių medžiagų, vertė. In silico ir in vitro patvirtinta, kad nauji 4-tiazolidinono dariniai su sulfanilamido, nitrofurano ir alilamino farmakoforais pasižymi prieš¬mikrobinėmis savybėmis prieš skirtingas bakterijų (S. aureus, E. faecalis, E. coli, P. aeruginosa, K. pneumonia, B. subtilis, P. mirabilis) ir grybelio C.albicans kultūras. Apibendrinus mikrobiologinių tyrimų rezultatus, nustatyti aktyviausi antibakteriniai ir priešgrybeliniai junginiai. / More than 200 antimicrobial agents are used in clinical practice for the treatment of infectious diseases, however, infectious diseases are still one of the most common causes of death, and the need for new antimicrobials isn’t decreasing. Compounds with different biological activity are synthesized by modifying 4-thiazolidinone. 4-thiazolidinones with sulfanilamide pharmacophore are more active against bacteria than sulfanilamides, and are characterized as antifungals. 4-thiazolidinones with nitrofuran pharmacophore are one of the most active antimicrobials. Higher antimicrobial activity of new compounds was expected after attaching allylamine to the molecule together with the previously known pharmacophores. By applying the selected methodologies for the synthesis of new 4-thiazolidinones with the fragments of selected pharmacophores (sulfanilamide, nitrofurane, allylamine), 39 derivatives of 4-thiazolidinone were synthesized. The assessment of physico-chemical properties and toxicity risk in silico helped to determine the value of compounds as biologically active substances. In silico and in vitro studies confirmed that new 4-thiazolidinone’s with sulfanilamide, nitrofurane and allylamine pharmacophores showed antimicrobial activity against various bacteria (S. aureus, E. faecalis, E. coli, P. aeruginosa, K. pneumonia, B. subtilis, P. mirabilis) and fungal cultures of C.albicans. Summarising microbiological tests, the most active antibacterial and antifungal compounds... [to full text]

Klinikinėje praktikoje infekcinėms ligoms gydyti vartojama daugiau kaip 200 priešmikrobinių medžiagų, tačiau infekcinės ligos yra viena dažniausių mirties priežasčių ir naujų priešmikrobinių vaistų poreikis nemažėja. Modifikuojant 4-tiazolidinono žiedą susintetinami įvairaus biologinio aktyvumo junginiai. 4-tiazolidinono dariniai su sulfanilamido farmakoforu yra aktyvesni už sulfanilamidus prieš bakterijas ir pasižymi priešgrybeliniu poveikiu; su nitrofurano farmakoforu yra vieni aktyviausių priešmikrobinių junginių. Alilaminą įjungus į molekulę kartu su jau anksčiau žinomais farmakoforais, tikėtąsi geresnio naujų junginių priešmikrobinio aktyvumo. Pritaikius pasirinktas metodikas naujų 4-tiazolidinono darinių su pasirinktų farmakoforų (sulfanilamido, nitrofurano, alilamino) struktūriniais fragmentais sintezei, susintetinti 39 4-tiazolidinono ciklą turintys junginiai. Įvertinus fiziko-chemines savybes ir toksiškumo riziką in silico, nustatyta junginių, kaip biologiškai aktyvių medžiagų, vertė. In silico ir in vitro patvirtinta, kad nauji 4-tiazolidinono dariniai su sulfanilamido, nitrofurano ir alilamino farmakoforais pasižymi prieš¬mikrobinėmis savybėmis prieš skirtingas bakterijų (S. aureus, E. faecalis, E. coli, P. aeruginosa, K. pneumonia, B. subtilis, P. mirabilis) ir grybelio C.albicans kultūras. Apibendrinus mikrobiologinių tyrimų rezultatus, nustatyti aktyviausi antibakteriniai ir priešgrybeliniai junginiai. / More than 200 antimicrobial agents are used in clinical practice for the treatment of infectious diseases, however, infectious diseases are still one of the most common causes of death, and the need for new antimicrobials isn’t decreasing. Compounds with different biological activity are synthesized by modifying 4-thiazolidinone. 4-thiazolidinones with sulfanilamide pharmacophore are more active against bacteria than sulfanilamides, and are characterized as antifungals. 4-thiazolidinones with nitrofuran pharmacophore are one of the most active antimicrobials. Higher antimicrobial activity of new compounds was expected after attaching allylamine to the molecule together with the previously known pharmacophores. By applying the selected methodologies for the synthesis of new 4-thiazolidinones with the fragments of selected pharmacophores (sulfanilamide, nitrofurane, allylamine), 39 derivatives of 4-thiazolidinone were synthesized. The assessment of physico-chemical properties and toxicity risk in silico helped to determine the value of compounds as biologically active substances. In silico and in vitro studies confirmed that new 4-thiazolidinone’s with sulfanilamide, nitrofurane and allylamine pharmacophores showed antimicrobial activity against various bacteria (S. aureus, E. faecalis, E. coli, P. aeruginosa, K. pneumonia, B. subtilis, P. mirabilis) and fungal cultures of C.albicans. Summarising microbiological tests, the most active antibacterial and antifungal compounds... [to full text]

Orientador: Ary Fernandes Junior / Banca: Rosemeire C. L. R. Pietro / Banca: Maria de Lourdes Ribeiro da Cunha / Resumo: Esta dissertação encontra-se dividida em introdução geral e 3 capítulos, sendo estes no formato de manuscritos a serem enviados para publicação em 3 periódicos distintos. Considerando a crescente utilização dos produtos naturais, especialmente dos obtidos a partir de plantas, objetivou-se estudar a ação antibacteriana de 27 óleos essenciais de uso em aromaterapia, sobre linhagens de Staphylococcus aureus (n=10), Escherichia coli (n=9), e Pseudomonas aeruginosa (n=9), isoladas de casos clínicos humanos, utilizando a metodologia dos discos (difusão) e determinação da concentração inibitória mínima (CIM) (diluição) em Mueller Hinton Ágar (Capítulo I). Verificou-se que as linhagens de S. aureus foram mais susceptíveis que as de Gram negativas, sendo que os valores de CIM90% foi de 0,21mg/mL para os óleos de pimenta negra (Piper nigrum) e tea tree (Melaleuca alternifolia) e 26,52mg/mL para o óleo de copaíba (Copaíba officinalis). Para E. coli, o óleo de canela (Cinnamomum cassia) foi o mais efetivo, com 2,0 mg/mL para CIM90% enquanto para P. aeruginosa o valor foi de 8,29 mg/mL com cravo da índia (Syzigium aromaticum). Utilizando valores de CIM obtidos in vitro foram selecionados 5 óleos (cravo da índia-Syzygium aromaticum, gerânio-Pelargonium graveolens, lavanda -Lavandula angustifolia, palmarosa-Cymbopogon martini e tea tree-Melaleuca alternifolia) e novamente sobre linhagens de Escherichia coli, Staphylococcus aureus e Pseudomonas aeruginosa, foi verificada a ação antibacteriana através da diluição individual de cada óleo em água e salina visando redução na contagem bacteriana em função do tempo (Capítulo II). Tanto nos ensaios em água quanto salina, verificou-se que o perfil de sensibilidade das linhagens bacterianas aos óleos essenciais foram próximos entre si, porém significativamente distintos comparados aos ensaios controles... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This thesis is divided into general introduction and three chapters, which are in the format of manuscripts to be submitted for publication in three separate journals. Considering the increasing use of natural products, especially those obtained from plants, aimed to study the antibacterial activity of 27 essential oils used in aromatherapy, on Staphylococcus aureus (n=10), Escherichia coli (n=9), and Pseudomonas aeruginosa (n=9), isolated from human clinical cases, using the methodology of the disks (diffusion) and determination of minimum inhibitory concentration (MIC) (dilution) on Mueller Hinton Agar (Chapter I). It was found that the strains of S. aureus were more susceptible than the Gram negative, and the values of MIC90% was 0.21 mg/mL for the oils of black pepper (Piper nigrum) and tea tree (Melaleuca alternifolia) and 26.52 mg/mL for oil Copaiba (Copaiba officinalis). For E. coli strains, the oil of cinnamon (Cinnamomum cassia) was the most effective, with 2.0 mg/mL for MIC 90% while for P. aeruginosa, the value was 8.29 mg/mL with clove (Syzigium aromaticum). Using MIC values obtained in vitro were selected five oils (cloves-Syzygium aromaticum, geranium-Pelargonium graveolens, lavender- Lavandula angustifolia, palmarosa-Cymbopogon martini and tea tree-Melaleuca alternifolia) and the bacteria Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, antibacterial activity was checked by dilution of individual oil and saline water in order to reduce the bacterial count in function of time (Chapter II). Both tests in saline and water, it was found that the sensitivity of bacterial strains to essential oils were close together, but were significantly different compared to control tests. Essential oils have demonstrated the potential inhibitor of the three bacterial strains, and the results were different from those obtained in vitro-ágar with Gram negative... (Complete abstract click electronic access below) / Mestre

Buscou-se identificar e comparar a atividade antibacteriana do extrato alcoólico de três acessos de Allium tuberosum - Rottler ex Sprengl – Liliaceae - originários da região metropolitana de Porto Alegre/RS frente a agentes de toxinfecções alimentares, especificamente: Staphylococcus aureus (ATCC 25.923), Enterococcus faecalis (ATCC 19.433), Salmonella Enteritidis (ATCC 11.076) Escherichia coli (ATCC 11.229). Inicialmente, in vitro, através de Teste de Diluição, por meio de Sistema de Tubos Múltiplos e o emprego de desinibidores bacterianos, determinou-se a Intensidade da Atividade de Inibição Bacteriana (IINIB) e a Intensidade de Atividade de Inativação Bacteriana (IINAB), revelando-se capacidades seletivas sobre os diferentes inóculos Gram-negativos, que atingiram inibição e inativação máximas e permanentes para Salmonella às 48 horas de confrontação inóculo/extrato, e às 72 horas de confrontação para Escherichia coli, respectivamente. As bactérias Gram-positivas ( Staphylococcus e Enterococcus) apresentaram resistência total nas diferentes confrontações. Não houve diferença significativa na atividade antibacteriana das três amostras de alho em estudo. Em um segundo momento, para um dos acessos de alho, através de Teste de Suspensão, determinou-se IINAB em duas simulações de preparação alimentar, requeijão cremoso e caldo de carne, condimentados com alho nirá, respectivamente. No modelo requeijão, E.coli mostrou-se completamente resistente em concentrações finais de 103, 104 e 105 U.F.C./mL, estas imediatamente acima da concentração máxima tolerada pela legislação brasileira, em três tempos de confrontação (24, 48, 72 horas), nas concentrações finais do extrato alcoólico de 10, 20 e 30 %, atendendo à legislação quanto à padrão de identificação e qualidade deste alimento. No caldo de carne, na concentração constante de 50 % de planta originalmente verde, Salmonella foi inativada totalmente na concentração de 105 U.F.C./mL já às 24 horas de confrontação, enquanto Escherichia atingiu este patamar às 48 horas de confrontação,Comenta-se, outrossim, o significado da inibição bacteriana demonstrada, relacionada à preditividade dos resultados de diagnóstico bacteriológico em protocolos de investigação de surtos toxinfectivos alimentares. / It was looked for to identify and to compare the antibacterial activity of the alcoholic extract of three accesses of Allium tuberosum - Rottler ex Sprengl - Liliaceae - original from Porto Alegre (RS/BR) metropolitan area, confronted to alimentary toxic infections agents, specifically: Staphylococcus aureus (ATCC 25.923), Enterococcus faecalis (ATCC 19.433), Salmonella Enteritidis (ATCC 11.076) Escherichia coli (ATCC 11.229). Initially, in vitro, through Test of Dilution, System of Multiple Tubes and the use of bacterial uninhibitors, was determined the Intensity of the Activity of Bacterial Inhibition (IINIB) and the Intensity of Activity of Bacterial Inactivation (IINAB), being revealed selective capacities on the different Gram-negative inoculums, that reached inhibition and maximum and permanent inactivation for Salmonella at 48 hours of confrontation inoculum/extract, and 72 hours of confrontation for Escherichia coli. The Gram-positive bacteria (Staphylococcus and Enterococcus) presented total resistance in the different confrontations. There was not significant difference in the antibacterial activity of the three accesses of garlic in study. Subsequently, for one of the samples of garlic, through Test of Suspension, was determined IINAB in alimentary simulation of creamy cheese seasoned with alcoholic extract in final concentration of 10, 20 and 30%, assisting to the legislation as for to identification pattern and quality of this food; as well as in simulation of alimentary preparation of bouillon, with the plant recently picked, in the final concentration of 50%. In the model creamy cheese, E.coli was shown completely resistant in final concentrations of 103, 104 and 105 U.F.C./mL, these immediately above the maximum concentration tolerated by the Brazilian legislation, in three times of confrontation (24, 48, 72 hours), in all of the final concentrations of the alcoholic extract. In the conditions of the simulated bouillon, Salmonella was totally inactivated in the concentration of 105 U.F.C./mL already at 24 hours of confrontation, while Escherichia reached this point at 48 hours of confrontation. Is commented, likewise, the meaning of the demonstrated bacterial inhibition, related to the prediction of the results of bacteriological diagnosis in protocols of alimentary toxic infective outbreaks investigation.