Publicação
Biological activity of naphthoquinones: Cytotoxic activity against eukaryotic plant cells and against eukaryotic human cells. Antimicrobial activity of naphthoquinones against selected microorganisms
| Resumo: | Infections caused by bacteria resistant to antimicrobial therapy are more and more frequent. Bacteria acquire resistance through genetic mutations that occur naturally, but this process has been accelerated due to the misuse of antibiotics. In fact, antibiotics have been overprescribed and even used over the counter, not to mention the extensive use of antibiotics in food-producing animals and plants. Antimicrobial resistance has become a worldwide public health problem, causing persistent infections, increased treatment costs, disability and death. Bacteria are growing resistant to last resource treatments and the pipeline for antimicrobial drugs is practically empty. It is urgent to invest in Research and Development to find new alternatives to fight multi-resistant bacteria, specifically for Gram-negative bacteria, which raise more concern because of the threat they represent in health care. Natural products constitute a possible solution for the antimicrobial resistance problem, due to their antimicrobial and resistance-modifying proprieties. Natural phenolic compounds can be emphasised for their potential to be used in humans as antibiotics. Naphthoquinones are phenolic compounds widespread in nature, that have been profoundly studied for their antitumoral proprieties, and also exhibit a strong antibacterial activity. Their mechanism of action often comprises the formation of reactive oxygen species, through oxide/reduction reactions, and they can accept one or two electrons, forming highly reactive radicals. Eight naphthoquinones have been tested for their toxicity and then used to test the sensibility with Micrococcus luteus, Escherichia coli and Saccharomyces cerevisiae. Every compound tested was toxic on human cells, except for 2-hydroxy-1,4-naphthoquinone. The compound 2-methoxy-1,4-naphthoquinone was in the borderline between toxicity and moderate toxicity. The first compound revealed a broad range of activity, being able to reduce the growth of all the selected microorganisms. The second one only showed antimicrobial activity against Escherichia coli and Saccharomyces cerevisiae. For statistically significative conclusions, experiments should be repeated, once this work was focused on optimizing the approaches and selecting the best experimental conditions. |
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| Autores principais: | Pedrosa, Inês Duarte Ferreira |
| Assunto: | Naphthoquinones Antimicrobial activity Antimicrobial resistance Biological activity Mestrado Integrado - 2017 |
| Ano: | 2017 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Infections caused by bacteria resistant to antimicrobial therapy are more and more frequent. Bacteria acquire resistance through genetic mutations that occur naturally, but this process has been accelerated due to the misuse of antibiotics. In fact, antibiotics have been overprescribed and even used over the counter, not to mention the extensive use of antibiotics in food-producing animals and plants. Antimicrobial resistance has become a worldwide public health problem, causing persistent infections, increased treatment costs, disability and death. Bacteria are growing resistant to last resource treatments and the pipeline for antimicrobial drugs is practically empty. It is urgent to invest in Research and Development to find new alternatives to fight multi-resistant bacteria, specifically for Gram-negative bacteria, which raise more concern because of the threat they represent in health care. Natural products constitute a possible solution for the antimicrobial resistance problem, due to their antimicrobial and resistance-modifying proprieties. Natural phenolic compounds can be emphasised for their potential to be used in humans as antibiotics. Naphthoquinones are phenolic compounds widespread in nature, that have been profoundly studied for their antitumoral proprieties, and also exhibit a strong antibacterial activity. Their mechanism of action often comprises the formation of reactive oxygen species, through oxide/reduction reactions, and they can accept one or two electrons, forming highly reactive radicals. Eight naphthoquinones have been tested for their toxicity and then used to test the sensibility with Micrococcus luteus, Escherichia coli and Saccharomyces cerevisiae. Every compound tested was toxic on human cells, except for 2-hydroxy-1,4-naphthoquinone. The compound 2-methoxy-1,4-naphthoquinone was in the borderline between toxicity and moderate toxicity. The first compound revealed a broad range of activity, being able to reduce the growth of all the selected microorganisms. The second one only showed antimicrobial activity against Escherichia coli and Saccharomyces cerevisiae. For statistically significative conclusions, experiments should be repeated, once this work was focused on optimizing the approaches and selecting the best experimental conditions. |
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