http://repositorio.ufc.br/handle/riufc/56325 Sat, 18 Apr 2026 06:13:31 GMT 2026-04-18T06:13:31Z http://repositorio.ufc.br/handle/riufc/85306 Título: Atividade antibacteriana e antibiofilme de óleorresinas extraídas de duas espécies de copaíba contra Staphylococcus aureus e avaliação da toxicidade Autor(es): Farias, Livia Pontes Abstract: Healthcare-associated infections (HAIs) affect patients under medical care during or after hospital admission, and are associated with numerous deaths annually, directly impacting global public health. This problem is exacerbated by the presence of strains exhibiting antimicrobial resistance, potentially leading to the ineffectiveness of antibiotic therapies. In this context, Staphylococcus aureus is a pathogen of great importance due to its frequent association with HAIs. The genus Copaifera, used in folk medicine due to its biological properties, stands out for its oleoresin production, with various pharmacological effects reported in the literature. Therefore, this study aimed to analyze the antimicrobial and antibiofilm activity of oleoresins extracted from C. arenicola (OCa) and C. langsdorffii (OCl) against S. aureus strains, as well as to evaluate their toxicity against cell lines (L929 and HaCaT) and Artemia salina. Regarding the results, both oleoresins showed Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values ​​between 125 and 500 μg/mL. For the non-volatile fractions of both species, the values ​​were 31.25 to 62.5 μg/mL for MIC and 31.25 to 125 μg/mL for MBC. For the major compounds, the concentrations ranged from 15.625 to 125 μg/mL for both MIC and MBC. The oleoresins also significantly inhibited biofilm formation, with reductions in viable cells ranging from 1 to 8.33 logs, a decline in biomass between 84.6 and 100%, and a decrease in metabolic activity between 67.80 and 100%. In pre-formed biofilms, reductions ranged from 0.71 to 2.71 logs of viable cells; decreases between 56.77% and 86.58% in total biomass; and from 17.77% to 92.62% in metabolic activity. Regarding Scanning Electron Microscopy, a reduction in cell quantity and extracellular matrix was observed, in addition to altered morphology after treatment with oleoresins in the CIM. In the cell viability assay, for both cell lines, the oleoresins showed cytotoxicity starting at a concentration of 250 μg/mL. Regarding A. salina, OCa showed a toxic effect starting at a concentration of 125 μg/mL, and OCl at 250 μg/mL. In light of the above, both oleoresins showed antibacterial and antibiofilm activity against the tested S. aureus strains, and most did not exhibit toxicity at concentrations lower than 250 μg/mL for the cell lines and A. salina. Thus, both oleoresins have promising potential against infections and biofilm formation associated with S. aureus Tipo: Dissertação Mon, 01 Jan 2024 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/85306 2024-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85049 Título: Avaliação in vitro da atividade antimicrobiana do Haloperidol em células planctônicas e biofilme de Candida spp. sensível e resistentes ao Fluconazol: determinação do possível mecanismo de ação Autor(es): Oliveira, Leilson Carvalho de Abstract: Fungal infections are particularly noteworthy due to their high morbidity and mortality rates. Estimates suggest that 1 billion individuals may have or live with some type of fungal infection, which is estimated to cause 3.8 to 4 million deaths annually. Candidiasis is the most prevalent opportunistic fungal infection worldwide, caused by yeasts of the genus Candida and exhibiting a high prevalence of clinical isolates resistant to conventional antifungals, making the development of new therapies paramount. In this context, drug repositioning is a strategy that aims to utilize medications already available on the market for purposes different from their initial use, for which haloperidol, a first-generation antipsychotic, has demonstrated potential in the antimicrobial field. From this perspective, the present study aims to evaluate the activity of haloperidol, alone and in combination with classic antifungals, against fluconazole-sensitive and fluconazole-resistant clinical strains of Candida spp., and the possible mechanisms associated with its antifungal action. Broth microdilution tests were performed to determine the Minimum Inhibitory Concentration (MIC), as indicated in the Clinical & Laboratory Standards Institute document M27-A3, for haloperidol and antifungals, along with checkerboard assays and the fractional inhibitory concentration index, flow cytometry, DNA damage assessment by comet assay, assays of formed and forming biofilms, and biofilm assessment by SEM. The results showed MICs of haloperidol ranging from 26.67 to 256 μg/mL. Regarding drug interaction assays, synergistic interactions were found between haloperidol and azoles, fluconazole and itraconazole, respectively, and 12.5% synergism with amphotericin B. The results also revealed that haloperidol induces apoptotic processes in C. albicans and C. auris species, causing DNA damage and methylation and inducing the expression of genes related to oxidative stress, contributing to homeostatic dysregulation, causing severe damage and inducing cell death. Biofilm assays showed a reduction in the viability of the formed biofilm in all species tested, ranging from 34.91% to 51.30% at the MIC concentration of the strains. Similar behavior was observed in the forming biofilm, where the reduction in viability ranged from 38.99% to 51.32%. Thus, haloperidol has great potential for antifungal action and stands out as a promising therapeutic alternative that needs further scientific investigation for future uses with anti-Candida action Tipo: Dissertação Thu, 01 Jan 2026 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/85049 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85016 Título: Avaliação da ação da DNase I em associação com a clorexidina em biofilmes de Streptococcus mutans formados sob exposição a diferentes açúcares Autor(es): Lima, Fábio Ruan Louzeiro Abstract: Dental caries is a disease that is related to biofilm and is influenced by diet. The oral biofilm matrix contains extracellular DNA (eDNA), which is a crucial component. This study aimed to examine the impact of combining DNase I and chlorhexidine on the formation of a S. mutans UA159 biofilm in vitro. Additionally, the study investigated the effects of exposure to various sugars. Biofilms were formed on hydroxyapatite disks (n=18) and in microtiter plates (n=18) under one of the following conditions: the biofilm formation was analyzed using 0.9% NaCl, 10% sucrose, or 5% glucose with 5% fructose. DNase was applied at the early stage of biofilm formation for 6 h (24-well plates) or 16 h (disks) and CHX was applied at the end for 5 min. The biofilms were harvested to analyze dry weight, colony forming units (CFU), biomass, viable bacteria, and polysaccharide formation. The results indicate that DNase did not increase CHX activity. Moreover, biomass and polysaccharide formation were higher when expose to sucrose. Further studies are needed to better understand the interaction between DNase and chlorhexidine for oral biofilm control. Tipo: Dissertação Sun, 01 Jan 2023 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/85016 2023-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/84459 Título: Genótipo de Helicobacter pytori na etiologia do câncer gástrico: correlação com metilação e expressão gênica Autor(es): Alves, Markênia Kélia Santos Abstract: Helicobacter pylori (H. pylori) is a relevant etiological factor associated with gastric cancer, although the mechanism by which it acts is still not well known, it is suggested a role of this microorganism in the promotion of methylation of DNA. In fact, gene silencing by metiiylation of promoter regions is highly frequent in gastric cancer. Thus, the present study aimed to evaluate the inactivation of the genes COX-2, CDKN2A and HMLH1 by methylation and its relationship with infection by H. pylori, in a series of gastric adenocarcinomas, in association with clinical and histopathological findmgs. This observational transversal study analyzed a sample of 82 gastric adenocarcinomas. The detection of H. pylori was done by amplification of the ureaseC gene, using the PCR technique, as well as the detection of the cagA, cagE, virBlï,flaA genes and the subtypes of the vacA gene. The pattern of expression and methylation of the COX-2, HMLH1 and CDKN2A genes was determined by immunohistochemistry and MS-PCR techniques, respectively. Statistically significant differences were evaluated by the chi-square test (^) or Fisher exact test and the results were considered statistically significant when the ^-values were less than 0.05. The most methylated gene was COX-2 (51.2%), followed by CDKN2A (46.3%) and HMLH1 (32.9%). The positivity ofCOX-2, HMLH1 and pl6INK4A was observed in 26%, 58.4% and 40.3% of the cases. A strong negative correlation was found between negativity of these markers and the presence of methylation in the promoters of their genes. In cárdia tumors, negativity of pl6IN was a significant finding (p=0.031), as well as the methylation in the promoter of COX-2 in intestinal tiunors of advanced stages (p=0.037). On the other hand, in noncardia tumors, the intestinal subtype lesions demonstrated a significant (p=0.006) inactivation of HMLH1 by methylation, while in the diffuse subtype tumors, a significant finding (p=0.022) was the negativity of CDKN2A by methylation. The infection by H. pylori was observed m 95.1% of the tumors. Considering the bacterial genotype, the genes vocA slml (70.5%) and flaA. (61.9%) were the most frequent. It was observed that the tumors with methylated COX-2 and HMLH1 genes were associated with the strains of H. pylori vacA sl (p= 0.028 and 0.047, respectively) and the non-methylated tumors were associated with the presence of the gene flaA (p=0.017). No correlation was found between the genes of H. pylori and absence of expression of the studied markers. These data suggest that the inactivation of the genes COX 2, HMLH1 and CDKN2A by methylation occur by distinct ways according to the histological subtype and tumor location and depends on the H. pylori genotype. Tipo: Dissertação Fri, 01 Jan 2010 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/84459 2010-01-01T00:00:00Z