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Síntese de derivados desidratados do diterpeno cafestol e docking molecular direcionado a alvos envolvidos no aumento de colesterol

2026-03-25T03:00:14Z

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

Caracterização química do extrato do epicarpo de Acrocomia aculeata e avaliação das atividades antioxidante e antimicrobiana

2026-03-25T03:00:14Z

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

Condições melhoradas de hidrólise de compostos fenólicos ligados em feijão (Phaseolus vulgaris) e jabuticaba (Myrciaria cauliflora)

2026-03-22T03:00:13Z

Title: Condições melhoradas de hidrólise de compostos fenólicos ligados em feijão (Phaseolus vulgaris) e jabuticaba (Myrciaria cauliflora) Author(s)/Inventor(s): Santos, Caroline Andrade dos Advisor: Monteiro, Mariana Costa Abstract: Sequential hydrolysis in alkaline and acidic media is widely used to extract insoluble phenolic compounds from foods, and their conditions determine the extraction yield. This study evaluated the effect of these conditions on the extraction of phenolic compounds from black beans (Phaseolus vulgaris) and jabuticaba (Myrciaria cauliflora). For alkaline hydrolysis, a 2³ factorial design was used, varying the NaOH concentration (2 M, 6 M and 10 M), time (30 min, 495 min and 960 min) and temperature (30 ºC, 45 ºC and 60 ºC). Acid hydrolysis followed a 2² factorial design, with HCl concentration (1.0 M, 6.5 M and 12.0 M) and time (20, 40 and 60 min), setting the temperature at 85 ºC. To describe the binding profiles of insoluble phenolic compounds with the food matrix in black beans, enzymatic hydrolysis was performed with the enzyme CeluMax® and porcine liver esterase. The phenolic compounds were analyzed by high-performance liquid chromatography (HPLC) and the data were treated by ANOVA and Tukey's post-test. In beans, the soluble fraction presented the anthocyanin delphinidin-3-O-glucoside as the main flavonoid (61% of the total), followed by petunidin-3-O-glucoside (20%) and malvidin-3-O-glucoside (10%). After alkaline hydrolysis, the predominant compounds were quercetin-3-O-glucoside and kaempferol-3-O-glucoside, representing 81% of the total content. The highest extraction occurred under conditions 2 (10 M NaOH; 30 min; 30 ºC) and 6 (10 M NaOH; 30 min; 60 ºC), suggesting that high NaOH concentrations associated with short times optimize the process, reducing the time required compared to usual protocols (up to 16 h). Acid hydrolysis allowed the identification of quercetin and kaempferol, but without statistical significance, indicating that extraction can be performed only in the alkaline stage, reducing costs and analysis time.The total content of phenolic compounds after hydrolysis with the CeluMax® enzyme (7.49 g/100 g) was statistically higher than that observed after hydrolysis with pork liver esterase (2.06 g/100 g). These results suggest that, in black beans, insoluble phenolic compounds are mostly linked to cellular structures through beta-glycosidic bonds. In jabuticaba, the anthocyanins cyanidin-3-O-glucoside (70%) and delphinidin-3-O-glucoside (15%) were the predominant compounds in the soluble fraction. After hydrolysis, gallic and ellagic acids were identified, with the former predominating. The most efficient conditions for extraction of phenolic compounds were 7 (2 M NaOH; 960 min; 60 ºC) and 9 (6 M NaOH; 495 min; 45 ºC), demonstrating that high times and temperatures favor the release of the compounds. The most efficient acid hydrolysis occurred in condition 3 (1 M HCl; 60 min), evidencing that lower concentrations of HCl can be used, making the process safer and more 8 sustainable. Furthermore, the possibility of reducing NaOH consumption is advantageous, since dissolutions in high concentrations require heating. Overall, the results indicate that the extraction of phenolic compounds can be optimized with less use of aggressive reagents and reduced times, making the method faster, more economical and environmentally sustainable compared to the methodologies described in the literature. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação

Efeito do tratamento térmico na textura e na bioacessibilidade protéica no desenvolvimento de um produto cárneo para pessoas acima dos 60 anos

2026-03-14T03:00:15Z

Title: Efeito do tratamento térmico na textura e na bioacessibilidade protéica no desenvolvimento de um produto cárneo para pessoas acima dos 60 anos Author(s)/Inventor(s): Capistrano, Ana Beatriz de Oliveira Advisor: Cabral, Lourdes Maria Corrêa Abstract: This study aimed to evaluate the effect of sample size (TA) and thermal lethality time (F₀) on the texture and protein bioaccessibility of beef strips processed in an autoclave and packed in flexible pouches. Seven experimental formulations were prepared: P1 (1 cm, 6 min), P2 (1 cm, 14 min), P3 (3 cm, 6 min), P4 (3 cm, 14 min), P5 (2 cm, 14 min), P6 and P7 (2 cm, 10 min). Samples were cut into cubes of approximately 2.5 cm in width and 5 cm in length, varying only in thickness according to the proposed TA. After processing, the following parameters were analyzed: texture (hardness, elasticity, chewiness, gumminess, shear force) and protein bioaccessibility (nitrogen recovery rate, degree of hydrolysis, and tyrosine release), with statistical analyses performed at a 5% significance level (p < 0.05). Results showed that sample size was the main factor influencing texture. Samples with TA = 1 cm presented lower shear force (5.68 ± 0.62 N in P1; 6.04 ± 1.15 N in P2) and greater tenderness, while 3 cm samples showed significantly higher values (54.55 ± 4.60 N in P3; 58.87 ± 7.86 N in P4), indicating increased mechanical resistance (p < 0.001). Hardness ranged from 17.48 ± 2.08 N (P2) to 61.18 ± 6.50 N (P3), and chewiness followed a similar pattern, from 2.21 ± 0.17 N (P2) to 14.66 ± 1.34 N (P3). Elasticity decreased with increasing F₀, with a significant difference between P1 and P4 (p = 0.037). Gumminess was affected by the interaction between TA and F₀, ranging from 5.66 ± 0.35 N (P2) to 22.47 ± 1.80 N (P3) (p < 0.01).Regarding protein bioaccessibility, P1 exhibited the highest nitrogen recovery rate (67.14%), while the lowest value was observed in P6 (49.58%). The degree of hydrolysis was highest in P3 (47.48 ± 4.34%), suggesting greater protein breakdown under 3 cm TA and 6 min F₀. Tyrosine release was more pronounced in intermediate samples (P6 and P7), reaching 766.67% an 758.34%, respectively. It is concluded that the modulation of TA and F₀ significantly influences meat texture and protein bioaccessibility. Smaller samples (TA = 1 cm), combined with short or intermediate processing times, resulted in better tenderness and greater protein retention. These conditions are promising for the development of meat products targeted at populations with specific needs, such as the elderly or individuals with chewing difficulties. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação