http://hdl.handle.net/11422/21 Tue, 21 Jul 2026 10:15:09 GMT 2026-07-21T10:15:09Z http://hdl.handle.net/11422/29304 Title: Study of the antitumoral mechanism of tarin, a lectin from taro (Colocasia esculenta L. Schott), in its free or nano-encapsulated forms, in pre-clinical trials in carcinoma models Author(s)/Inventor(s): Cardoso, Raiane Vieira Advisor: Paschoalin, Vânia Margaret Flosi Abstract: Tarin is a purified lectin from yam (Colocasia esculenta L. Schott), belonging to the family of lectins related to GNA (Galanthus nivalis agglutinin), which has outstanding immunomodulatory and antitumor properties. When nano-encapsulated in pegylated liposomes, tarin has its stability and bioavailability increased, promoting controlled and sustained release, which enhances its biological effects and reduces cytotoxicity on normal cells. The present study evaluated the molecular mechanisms involved in the antitumor activity of nano-encapsulated tarin in two human tumoral cell lines treated for 24 and 48 h, the breast adenocarcinoma (MDA-MB-231) and glioblastoma (U-87 MG), two in vitro models widely used to study therapies against aggressive tumors. The analyses were conducted by flow cytometry, transmission electron microscopy (TEM) and cell migration assay (scratch assay) and proteomics. In addition, the transport of nano-encapsulated tarin across the blood-brain barrier (BBB) model was evaluated using hCMEC/D3 endothelial cells, demonstrating that the formulation is able to cross BBB efficiently, which reinforces its potential for the treatment of tumors from the central nervous system. Exposure to nano-encapsulated tarin also resulted in significant inhibition of cell proliferation and migration, without causing cytotoxic effects on healthy human fibroblasts. Nano-encapsulated tarin induces cell tumoral death by apoptosis and autophagy-dependent mechanisms. Treated-tumoral cells showed increased autophagosome formation, activation of caspases 3/7 and cell cycle arrest in the G0/G1 phases forMDA-MB-231 cells, and G2/M for U-87 MG A global proteomic analysis using mass spectrometry was performed to identify changes in protein expression and to clarify the molecular mechanisms involved in the cellular response to the antitumor formulation. The treatment modulated key proteins such as PARK7, OPA1, CHEK1, LAMA4, and HLA-A, indicating effects on oxidative stress regulation, mitochondrial dynamics, cell-cycle control, extracellular matrix remodeling, and antigen presentation. These alterations suggest that the action of nano-encapsulated tarin goes beyond direct cytotoxicity, promoting a functional reprogramming that destabilizes tumor homeostasis and favors the coordinated activation of cell death pathways. It seems that the cell death involves several processes that occur in an interdependent way, where the initial stress induced by exposition to tarin triggers autophagic responses, followed by the activation of apoptotic mechanisms and, consequently, by the inhibition of cell proliferation and migration. Together, these findings show that nano-encapsulated tarin exerts a multifactorial antitumor effect, acting on different pathways to control cell survival, and reinforce its potential as a promising candidate for the development of innovative and selective antitumor therapies, applicable to different types of human carcinoma, including breast cancer and glioblastoma. Publisher: Universidade Federal do Rio de Janeiro Type: Tese Wed, 01 Jan 2025 00:00:00 GMT http://hdl.handle.net/11422/29304 2025-01-01T00:00:00Z http://hdl.handle.net/11422/29267 Title: A theorical practical approach to sourdough starter: microbiology and drying processes Author(s)/Inventor(s): Albagli, Gabriel Advisor: Sécca, Priscilla Filomena Fonseca Amaral Abstract: Sourdough starter is prepared by mixing flour (traditionally wheat or rye) and water and left to ferment in room temperature (25 – 30 °C). It is a process based on interaction between bacteria (mainly lactic acid bacteria) and yeast (mainly S. cerevisiae and Candida species) present in the ingredients and the tools used, being used as a starter culture in bread making. The final product has enhanced sensorial, functional and nutritional properties. Although it has advantages over baker’s yeast, sourdough needs time and dedication to maintain the microflora viable through the backslopping process, where flour and water is added and the mix is left to ferment in room temperature, this needs to be done every time sourdough is used. Drying techniques could be applied to stabilize the microbiota and avoid the backslopping. The objectives of this work were to gather scientific articles about drying techniques that could be applied to sourdough and perform a technological prospection concerning the starter microbiology, pointing out new technologies and future trends in the market. Freeze- and spray-drying are the most successful methods applied to sourdough, maintaining a good concentration of viable microbes. However, the conditions of the process can affect the microbe survivability. The number of scientific publications and patents has increased over the last 10 years, however no innovations in the market were made. The majority of the patents were deposited by companies while most of scientific articles were developed by universities. The scientific publication profile is different from the patent profile, most of the patents found were about the development of starter and products, while scientific publications concern manly about microbe selection, fermentation products and sourdough starter application. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação Sat, 01 Jan 2022 00:00:00 GMT http://hdl.handle.net/11422/29267 2022-01-01T00:00:00Z http://hdl.handle.net/11422/28942 Title: Síntese de derivados desidratados do diterpeno cafestol e docking molecular direcionado a alvos envolvidos no aumento de colesterol Author(s)/Inventor(s): Silva, Maria Alice Esteves da Advisor: Rezende, Claudia Moraes de Abstract: Cafestol, an ent-kaurane furanoditerpene from the lipid fraction of coffee beans (Coffea sp.), is a potent hypercholesterolemic agent resulting from the agonist action on the farnesoid X receptor (FXR) and the inhibition of cholesterol-7-α-hydroxylase (CYP7A1), two proteins involved in the regulation and biosynthesis of bile acids. During the roasting of coffee beans, cafestol undergoes thermal degradation, yielding the derivatives 15,16-dehydrocafestol and its regioisomers 13,16-dehydrocafestol and cafestal (tautomer of 16,17-dehydrocafestol). The formation of these substances is dependent on the intensity of roasting; consequently, deeply roasted beans, typically consumed in Brazil, present high concentrations of these dehydrated derivatives. Regarding these compounds, whose isolation from coffee beans is not simple by conventional chromatographic techniques, little information is known about their biological activities. Therefore, this dissertation aimed to synthesize the dehydrated products of cafestol present in roasted coffee beans and to preliminarily evaluate the potential binding modes of the roasting derivatives with the FXR receptor and the human CYP7A1 enzyme in molecular docking simulations. After the development of a three-step synthetic route and characterization of the products by mass spectrometry and one- and two-dimensional nuclear magnetic resonance, the products cafestal and 15,16-dehydrocafestol were identified. In the molecular docking simulations, cafestol and its derivatives showed similar affinities (kcal/mol) and types of interaction with amino acid residues in the different complexes with FXR and CYP7A1. By combining these in silico data with a new alternative to obtain these compounds, the evaluation of the hypercholesterolemic activity becomes favorable in the future. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação Fri, 28 Feb 2025 00:00:00 GMT http://hdl.handle.net/11422/28942 2025-02-28T00:00:00Z http://hdl.handle.net/11422/28940 Title: Caracterização química do extrato do epicarpo de Acrocomia aculeata e avaliação das atividades antioxidante e antimicrobiana Author(s)/Inventor(s): Santos, Fabiane da Conceição Vieira Advisor: Moreno, Daniela Sales Alviano Abstract: Acrocomia aculeata, popularly known as macaúba, is an oleaginous palm tree recognized for its great potential in biodiesel production. Despite its high productivity and great potential for waste reuse, the epicarp (shell) is still little explored in relation to its chemical composition and biological activity. In this sense, the objective of this study was to investigate the potential of the macaúba epicarp, an underutilized residue, as a new source of bioactive compounds. To this end, the study performed chemical characterization through the integration of techniques such as imaging mass spectrometry which allowed direct visualization of the spatial distribution of plant tissue compounds, and high-performance liquid chromatography coupled with mass spectrometry which allowed quantification and structural elucidation of the compounds present in the plant extracts. In addition, the study evaluated the antioxidant and antimicrobial potential and performed an in silico prediction for the isolated bioactives. The study identified compounds such as piceatannol, 3,4,5,3′,5′-pentahydroxy-trans-stilbene (PHS) and, in smaller amounts, resveratrol in epicarp extracts through techniques that confirmed the exclusive location of PHS and piceatannol in the fruit epicarp. Extraction with aqueous acetone (Me2CO:H2O) and its EtOAc fraction showed the highest yields of stilbenes and efficiently increases by 51.7 and 68.3%, respectively, the tolerance of Saccharomyces cerevisiae to oxidative stress induced by hydrogen peroxide. Furthermore, the EtOAc fraction showed moderate antibacterial activity against Bacillus subtilis (125 μg/ml), Staphylococcus aureus (125 μg/ml) and methicillin-resistant S. aureus (MRSA) (250 μg/ml). Additionally, it demonstrated significant anticryptococcal activity against three strains of Cryptococcus neoformans with minimum inhibitory concentration ranging from 7.8 to 15.26 μg/ml, with resveratrol and piceatannol by 60 and 70%, respectively, the survival rates of Galleria mellonella larvae infected with C. neoformans H99. In silico analysis indicates low toxicity for piceatannol, PHS and resveratrol, in addition to favorable pharmacokinetic parameters for oral bioavailability. Thus, the study concludes that macaúba epicarp is a valuable source of bioactive compounds with antioxidant and antimicrobial activity. Publisher: Universidade Federal do Rio de Janeiro Type: Tese Mon, 28 Apr 2025 00:00:00 GMT http://hdl.handle.net/11422/28940 2025-04-28T00:00:00Z