Portal de Pesquisa da BVS Veterinária

Tese em Português | VETTESES | ID: vtt-218454

Resumo

Dentre os organismos marinhos, as macroalgas vem sendo cada vez mais estudadas, pois desempenham papel fundamental tanto para o ecossistema como para a economia. A macroalga marinha parda, Sargassum vulgare, C. Agardh, 1820, foi coletada na Praia do Paracuru, municipio de Paracuru, Ceara, em fevereiro de 2019. Em laboratorio, a biomassa coletada foi lavada, liofilizada e usada para o processo de extracao com etanol, cujo rendimento foi de 1,52%. Uma parte do extrato etanolico (EtOH) foi reservada, e a outra foi submetida a cromatografia em coluna de silica gel com solventes de diferentes polaridades para a obtencao de seis fracoes: hexanica (Hx), diclorometano (DCM), acetato de etila (AcOEt), etanolica (EtOH), metanolica (MeOH) e aquosa (H2O). O extrato etanolico e suas fracoes foram analisados com o objetivo de quantificar os teores de compostos fenolicos totais (CFT) e flavonoides (TF) e determinar seus potenciais biologicos, pelas atividades antioxidante, fitotoxica e antimicrobiana. Os resultados de CFT foram 10,94 mg EAG/g (extrato) e variaram de 2,61 a 38,85 mg EAG/g (fracoes). Os valores de TF foram 108,63 mg EQ/g (extrato) e variaram de 1,68 a 158,09 mg EQ/g (fracoes). A capacidade de sequestro do radical DPPH variou de 10,58% a 16,57% no extrato e de 2,55% a 11,24% nas fracoes. O poder de quelacao de ions ferrosos (FIC) variou de 18,20% a 22,36% no extrato, enquanto nas fracoes, a variacao foi de 4,95% a 88,64%. O poder de reducao de ions ferricos (FRAP) variou de 0,080 a 0,143 no extrato e de 0,061 a 0,138 nas fracoes. A atividade inibitoria do branqueamento do -caroteno (BCB) variou de 90,76% a 96,70% no extrato e de 67,66% a 100% nas fracoes. No ensaio de fitotoxicidade com sementes de pepino caipira, Cucumis sativus, o extrato etanolico foi classificado como nao fitotoxico, enquanto as fracoes foram capazes de potencializar a germinacao e o crescimento das raizes, com excecao da fracao acetato de etila, que foi moderadamente fitotoxica. Os ensaios antimicrobianos de concentracao inibitoria minima (CIM) e de concentracao bactericida minima (CBM) exibiram valores entre 0,078 e 5,0 mg/mL. Os resultados deste trabalho revelaram que o extrato etanolico de S. vulgare e suas fracoes (Hx, DCM, AcOEt, EtOH, MeOH e H2O) possuem diferentes atividades biologicas com potencial para aplicacoes industriais e agricolas. Mais investigacoes sao necessarias para elucidar os mecanismos de acao responsaveis por essas atividades, e os procedimentos para usar esses compostos em produtos de interesse.

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Among marine organisms, macroalgae have been increasingly studied, as they play a fundamental role both for the ecosystem and for the economy. The brown seaweed, Sargassum vulgare, C. Agardh, 1820, was collected at Praia do Paracuru, Paracuru, Ceará, in February 2019. In laboratory, the biomass was washed, lyophilized and used for the extraction process with ethanol, whose yield was 1.52%. A part of the ethanol extract (EtOH) was reserved, and the other part was subjected to silica gel column chromatography with solvents of different polarities to obtain six fractions: hexane (Hx), dichloromethane (DCM), ethyl acetate (AcOEt), ethanolic (EtOH), methanolic (MeOH) and aqueous (H2O). The ethanol extract and its fractions were analyzed in order to quantify total phenolic compounds (TPC) and flavonoids, and to determine their biological potential, through antioxidant, phytotoxic and antimicrobial activities. The TPC results were 10.94 ± 2.08 mg EAG/g (extract) and ranged from 2.61 ± 0.06 to 38.85 ± 2.03 mg EAG/g (fractions). Flavonoid contents were 108.63 ± 3.62mg EQ/g (extract) and ranged from 1.68 ± 0.32 to 158.09 ± 6.38 mg EQ/g (fractions). The DPPH radical scavenging capacity ranged from 10.58% ± 0.91 to 16.57% ± 0.67 in the extract and from 2.55% ± 0.07 to 11.24% ± 0.99 in the fractions. The ferrous ion-chelating assay (FIC) of extracts ranged from 18.20% ± 0.00 to 22.36% ± 2.41, while this antioxidant activity varied from 4.95% ± 0.58 to 88.64% ± 1.90 in the fractions. The ferric reducing antioxidant power (FRAP) assay showed values ranging from 0.080 ± 0.013 to 0.143 ± 0.013 in the extract and from 0.061 ± 0.006 to 0.138 ± 0.009 in the fractions. The -carotene bleaching (BCB) inhibitory activity ranged from 90.76% ± 0.34 to 96.70% ± 0.67 in the extract and from 67.66% ± 1.07 to 101.87% ± 4.25 in the fractions. Phytotoxicity test on cucumber seeds (Cucumis sativus) indicated the ethanol extract as non-phytotoxic, while the fractions were able to enhance germination and root growth, with the exception of the ethyl acetate fraction considered as moderately phytotoxic. The antimicrobial assays of minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) showed values between 0.078 and 5.0 mg/mL. The results of this work revealed that the ethanol extract of S. vulgare and its fractions (Hx, DCM, AcOEt, EtOH, MeOH and H2O) possessed different biological activities with potential for both industrial and agricultural applications. Further investigation is required to elucidate the mechanisms of action responsible for these activities, and the procedures to use these compounds in products of interest

Biblioteca responsável: BR68.1