Credenciado pela CAPES como Mestrado Acadêmico, na área de Geociências, o PPGC&TAmb teve início com a atualização do seu Regimento Interno em outubro de 2022, conforme decisão do Conselho de Ensino, Pesquisa, Extensão e Inovação (Consepe). Este marco reforça o compromisso da UFMA em promover a excelência acadêmica e impulsionar o avanço científico e tecnológico na região. Esta Coleção contém os trabalhos do Mestrado Acadêmico. https://tedebc.ufma.br/jspui/handle/tede/5995 2026-06-25T19:38:02Z 2026-06-25T19:38:02Z FREITAS, Debora Serra https://tedebc.ufma.br/jspui/handle/tede/7068 2026-06-25T12:47:28Z 2025-09-24T00:00:00Z

Título: DESENVOLVIMENTO DE BIOINSUMOS PARA O CONTROLE DE INSETOS EM CULTIVOS DE ARROZ (O. sativa L.) Autor: FREITAS, Debora Serra Primeiro orientador: OLIVEIRA, Regina Maria Mendes de Abstract: The development of bioinputs represents a strategic and sustainable alternative for controlling insect pests in agricultural crops. Thus, the objective of this work was to develop natural formulations, including extracts of Azadirachta indica (neem), free lausone (from Lawsonia inermis) and complexed with magnesium ions, for the control of insect pests of stored grains. The methodology was structured in stages: diagnosis of the main rice pests; preparation of natural and treated plant extracts; synthesis and characterization of a magnesium-lausone coordination compound (Mg-bisla); preliminary toxicity testing on Artemia salina; and bioassays of insecticidal and repellent activity against Tribolium castaneum and Sitophilus zeamais. Analytical and spectroscopic characterization data indicate the formation of the Mg-bisla compound, which exhibits superior thermal stability to free lausone. Biological assays revealed that, although no significant mortality due to ingestion was observed in T. castaneum, fresh neem leaf powder showed a repellent effect, while treated neem and Mg-bisla exhibited attractive behavior. Free lausone showed significant repellency against T. castaneum. In contact tests, both lausone and Mg-bisla showed low efficacy in the mortality of S. zeamais (10%), being lower than commercial neem oil (30%). The reduced toxicity of Mg-bisla in A. salina suggests potential for safe application. In conclusion, the results demonstrate the selective potential of bioinputs in grain protection, reinforcing the importance of coordination chemistry as a tool for modulating biological properties. Instituição: Universidade Federal do Maranhão Tipo do documento: Dissertação

2025-09-24T00:00:00Z COSTA, Bárbara Beatriz Caxilé https://tedebc.ufma.br/jspui/handle/tede/7058 2026-06-18T13:36:33Z 2026-02-27T00:00:00Z

Título: ESTUDO DO POTENCIAL ANTIOXIDANTE DO EXTRATO ETANÓLICO DA AMBURANA CEARENSIS COMO FATOR DETERMINANTE NA ESTABILIDADE OXIDATIVA DO BIODIESEL DE SOJA Autor: COSTA, Bárbara Beatriz Caxilé Primeiro orientador: PASSOS, Ionara Nayana Gomes Abstract: This master’s thesis aims to investigate the oxidative stability of biodiesel through the use of an ethanolic extract obtained from the exudate of Amburana cearensis as a natural antioxidant additive. The incorporation of antioxidants is a widely used strategy to mitigate the oxidative degradation of biodiesel; however, synthetic antioxidants are often associated with high cost, potential toxicity, and low biodegradability, making the discovery of new chemical substances an area of significant scientific advancement. Experimental results for the ethanol extract of Amburana cearensis demonstrated antioxidant efficacy as determined by the ABTS •⁺ radical scavenging assay, which showed high antioxidant activity even with mass loss over time. Thermogravimetric and differential thermal analysis (TG/DTA) revealed its thermal stability at high temperatures, with degradation beginning at 281°C. Chemical characterization by HPLC and DI-ESI-IT-MSn identified the compounds responsible for the antioxidant activity; the predominant metabolite was associated with coumarins, flavonoids, and phenolic acids. Fragments of five compounds were identified as butein, calicosin, cirsimaritin, 3,5,3-trihydroxy-7,4-dimethoxyflavone, and nevadensiv. The extract’s efficacy as an antioxidant in biodiesel was evaluated using the Rancimat method (EN 14112). The treated sample exhibited an induction time of 11.03 h with 3000 ppm of the ethanolic extract, coming very close to the limits established by the National Agency of Petroleum, Natural Gas, and Biofuels (ANP). Overall, the phytochemicals present in the exudate of Amburana cearensis demonstrate significant scientific, environmental, and socioeconomic potential, supporting its use as a green and regional alternative to synthetic antioxidants. Instituição: Universidade Federal do Maranhão Tipo do documento: Dissertação

2026-02-27T00:00:00Z MATA, Raylane Rocha da https://tedebc.ufma.br/jspui/handle/tede/7042 2026-06-11T14:36:46Z 2026-02-26T00:00:00Z

Título: Atividade inseticida, fagoinibidora e repelente de extratos e frações de Solanum paniculatum sobre Sitophilus zeamais (coleoptera: curculionidae) Autor: MATA, Raylane Rocha da Primeiro orientador: PASSOS, Ionara Nayana Gomes Abstract: Post-harvest losses caused by insect pests represent one of the main factors responsible for the reduction in the quality and quantity of stored grains, with the maize weevil, Sitophilus zeamais, standing out as one of the species of greatest economic importance. In this context, the present study aimed to evaluate the bioinsecticidal potential of extracts and fractions obtained from the leaves of Solanum paniculatum in the control of S. zeamais. The plant extracts were obtained through an extraction process and subsequently fractionated using solvents of different polarities, being evaluated through laboratory bioassays of mortality and insecticidal activity. Additionally, qualitative phytochemical and chromatographic analyses were performed to identify the main secondary metabolites present. The results demonstrated high bioinsecticidal activity of the tested extracts and fractions, with emphasis on the crude extract and the acetate organic fraction, which showed high insect mortality rates. Chemical analyses indicated the presence of phenolic compounds, flavonoids, and lipophilic substances, metabolites frequently associated with insecticidal activity. Therefore, it is concluded that Solanum paniculatum presents promising potential as a source of natural compounds for the development of bioinsecticides applicable to the sustainable management of stored-grain pests. Instituição: Universidade Federal do Maranhão Tipo do documento: Dissertação; Documento sob sigilo. Prazo provável para disponibilização total: 3 anos. Motivo do sigilo: publicação de artigo.

2026-02-26T00:00:00Z OLIVEIRA, Rainara Ribeiro https://tedebc.ufma.br/jspui/handle/tede/7038 2026-06-08T12:06:40Z 2026-02-26T00:00:00Z

Título: Efeito alelopático de Solanum paniculatum para o controle sustentável da planta daninha Leucaena leucocephala Autor: OLIVEIRA, Rainara Ribeiro Primeiro orientador: OLIVEIRA, Regina Maria Mendes Abstract: Despite advances in agriculture, productivity losses still occur due to the presence of invasive plants, which represent a major obstacle to agricultural production. Based on this assumption, the objective of this study was to evaluate the allelopathic potential of the crude extract and fractions of Solanum paniculatum, compared to glyphosate, on Leucaena leucocephala. The leaves of S. paniculatum were collected in the municipality of Anapurus-MA and identified in the CCAA/UFMA Herbarium under voucher no. 5399. The material was dried, crushed, and subjected to extraction. Two hundred grams of leaves were used in 99.5% ethanol and water, subjected to percolation for 30 days. The preparation of the crude extract and fractions was carried out at the Natural Products Chemistry Laboratory (LQPN/CAMQ/UFMA), followed by chemical characterization. L. leucocephala was used as the recipient plant, testing concentrations of 2% and 5%. Bioassays of bioherbicidal potential were conducted in a completely randomized design (CRD), with four treatments (including positive and negative controls) in four replicates. Statistical analysis was performed using ANOVA, followed by Tukey's test (5%), using InfoStat® (2010) and Excel® (2019) software for data tabulation and interpretation. The study evaluated the allelopathic potential of Solanum paniculatum on Leucaena leucocephala from the crude hydroalcoholic extract (EBH) and its fractions. The EBH was the most active, inhibiting 95% of germination at 5%, in addition to reducing radicle growth (76% at 5%) and hypocotyl growth (70% at 5%). Among the fractions, acetate performed best, with 65% inhibition of the radicle at 5% and 66% of the hypocotyl at 5%. The hexane phase stood out at 2%, with 72% inhibition of the radicle, while the aqueous phase was most effective at 1%, inhibiting 56% of the hypocotyl. Instituição: Universidade Federal do Maranhão Tipo do documento: Dissertação; Trabalho sob Sigilo.Motivo do sigilo: Publicação do Trabalho.Submetido, ainda não publicado. Mas no ato da submissão foi feita uma declaração de direito autoral à revista. Prazo previsto para disponibilização total: 3 anos.

2026-02-26T00:00:00Z