Dissertações em Química (Mestrado) - PPGQ/ICEN
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/16399
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Item Acesso aberto (Open Access) Estudo fitoquímico e avaliação do potencial antimicrobiano e antioxidadnte das folhas de metrodorea flavida k. krause(Universidade Federal do Pará, 2023-09-29) CONCEIÇÃO, Carlos Maurício Nunes de Souza da; PINHEIRO, Wandson Braamcamp de Souza; http://lattes.cnpq.br/8867866033296703; SANTOS, Lourivaldo da Silva; http://lattes.cnpq.br/3232898465948962; SILVA, Milton Nascimento da; http://lattes.cnpq.br/6742390457977989; https://orcid.org/0000-0001-9755-4058The species Metrodorea flavida K. Krause, popularly known as three leaves, belongs to the Rutaceae family, and is an endemic species of the Amazon biome. Despite belonging to a taxon of economic and medicinal relevance, in addition to being located in one of the regions of the planet with the greatest biotechnological relevance, there is still a scarcity of studies focused on the phytochemistry of M. flavida for this species. Therefore, this work sought to contribute to the phytochemical study of this species, through the determination of the chemical, chromatographic and spectroscopic profiles of M. flavida extracts, the isolation and structural elucidation of the major compounds, as well as the evaluation of antioxidant potentials. and antimicrobial from M. flavida leaf extracts. Firstly, microextractions were carried out from the plant leaves with the solvents ethyl acetate, 96% ethanol and 70% ethanol. After analyzing the profiles obtained by High Efficiency Thin Layer Chromatography, High Efficiency Liquid Chromatography (HPLC), by Nuclear Magnetic Resonance and antioxidant and antimicrobial tests with the extracts, an extraction was carried out by maceration using 70% ethanol, of this extract. fractionation occurred with Solid Phase Extraction, resulting in 23 fractions, of which the constituents of fraction 60%V1 were purified by high-performance liquid chromatography, as well as the isolated substances were elucidated by 1D Nuclear Magnetic Resonance (NMR) spectroscopy and 2D. The chemical profiles of the M. flavida extracts indicated the presence of substances from the classes of terpenes, flavonoids and coumarins, the antioxidant tests of the extracts demonstrated that the microextract obtained with 70% ethanol presented greater efficiency in scavenging DPPH• radicals, in addition, for antimicrobial tests, the microextract obtained with ethyl acetate showed the best results for strains of Staphylococcus aureus, Bacillus subtilis and Escherichia coli. The 70% ethanol macerated extract was also tested for the same strains mentioned above and showed bactericidal action for S. aureus, B. subtilis and E. coli, in addition to bacteriostatic action for Salmonella typhimurium. From the 60%V1 fraction, five substances were isolated (S1, S2, S3, S4 and S5), which after analysis by NMR and thorough research on the Scinfinder and PubChem platforms, it was found that substances S2 and S4 are treated of two new dihydrochalcones, isolated for the first time from plants. In this way, the data obtained represent a contribution to the study of phytochemistry and the biological properties of the species M. flavida, as well as to the natural product chemistry, since two new natural compounds were discovered.Item Acesso aberto (Open Access) Estudo químico e atividades biológicas dos extratos do fungo actinomucor elegans accc18.1a endofítico de rhizophora mangle l. (rhizophoraceae)(Universidade Federal do Pará, 2024-02-26) PADILLA, Kathia Raquel Murillo; MARINHO, Patrícia Santana Barbosa; http://lattes.cnpq.br/4826647905254039; HTTPS://ORCID.ORG/0000-0002-9368-8574; MARINHO, Andrey Moacir do Rosário; http://lattes.cnpq.br/2511998363000599; https://orcid.org/0000-0002-8981-0995The study of underexplored natural sources, especially in the Amazon region, has gained significance in recent years. Considering the Amazon as the largest forest in the world, it is notable that many species still remain undiscovered. In this context, research on secondary metabolites of endophytic fungi has sparked growing interest in the scientific community, driven by the potential these microorganisms hold in the field of health. Microorganisms have been a rich source of bioactive metabolites with various applications such as agrochemicals, antibiotics, immunosuppressants, antiparasitic, and anticancer agents. The aim of this study was to contribute to the investigation of endophytic fungi in mangrove plants of the Brazilian Amazon through the isolation and identification of compounds with antimicrobial, allelopathic, and anticancer activities from the fungus Actinomucor elegans AcCC181A, which was isolated as an endophyte from the plant Rhizophora mangle L. (Rhizophoraceae). Using chromatography techniques, the phenolic compounds tyrosol (S-1), 4-hydroxyphenylacetic acid (S-2), 4-formylphenyl 2-phenylacetate (S-3), and phenylacetic acid (S-4) were isolated. From tyrosol, the substances 4-(2-acetoxyethyl)-phenylacetate (S-5), 4-(2-(butyryloxy)ethyl)- phenylbutyrate (S-6), and 4-(2-(benzoyloxy)ethyl)phenylbenzoate (S-7) were obtained through structural derivatization. The structures of the substances were elucidated using Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) techniques. The substances and crude extract were tested against the bacteria E. coli, Bacillus subtilis, S. typhimurium, S. aureus, and Xanthomonas axonopodis pv. passiflorae, showing antimicrobial activity results. Cytotoxicity and cell viability assays of the isolated substances S-1, S-2, and S-3 were also performed. All tested substances demonstrated potential cytotoxic activity on gastric cancer cell lines. Additionally, the allelopathic potential of the crude extract was evaluated, showing activity with lettuce seeds. It is important to note that compounds S-6, S-3, and S-7 are being tested for the first time in antimicrobial assays. Furthermore, it is relevant to emphasize that this study represents the first report of antimicrobial assays conducted with the substances isolated in this work against the bacteria Xanthomonas axonopodis pv. passiflorae.