Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11847
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Item Unprecedented one-pot sequence for the synthesis of tetrahydroquinoline alkaloids and preliminary evaluation of their antibacterial activity(Journal of the Brazilian Chemical Society, 2018-12) Purgato, Gislaine A.; Diaz, Marisa A. N.; Diaz-Muñoz, Gaspar; Miranda, Izabel L.; Sartori, Suélen K.; Dias, Gabriel N. S.; Kohlhoff, MarkusA novel one-pot sequence (in 2 or 3 steps) was developed for the synthesis of the tetrahydroquinoline alkaloids (±)-galipinine, (±)-cuspareine, (±)-galipeine and (±)-angustureine, and the derivative (±)-11-methoxy-5,6,6a,7,8,13-hexahydro-13a-aza-benzo[5,6]cyclohepta [1,2-a]naphthalene-12-ol from their respective Wittig adducts in moderate and high yields. The solvolytic N-methylation reaction was shown to be catalyzed by Pt0, generated in situ by reduction of PtO2. The evaluation of biofilm inhibition and antibacterial activity of the compounds against Staphylococcus aureus strains isolated from cows with mastitis revealed that the alkaloid derivative is a promising candidate for an antibiotic drug.Item Plant extracts display synergism with different classes of antibiotics(Anais da Academia Brasileira de Ciências, 2019-05) Silva, Danielle M.; Costa, Priscilla A. da; Ribon, Andréa O. B.; Purgato, Gislaine A.; Diaz-Muñoz, Gaspar; Diaz, Marisa A.N.One manner in which plant-derived compounds exert their antibiotic potential is the synergism, a positive interaction between two compounds. Studies indicate that the use of plant extracts combined with antimicrobials may promote a significant reduction of the minimum inhibitory concentrations of antibiotics for bacterial strains. This study aimed to evaluate the activity of plant extracts and antibiotics as well as their combination on Staphylococcus aureus. The activity of 15 plant extracts was evaluated using diffusion assay. The minimum inhibitory concentrations (MICs) and the interactions between the extracts and antibiotics as well as compound emodin were evaluated with the checkerboard method. The active extracts were a hexane extract of the leaves of Baccharis dracunculifolia and the ethanol extracts of the leaves of Plectranthus ornatus, Inga edulis, Salvia officinalis and Senna macranthera. The Plectranthus ornatus extract displayed synergism with ampicillin (a β-lactam), kanamycin and gentamicin (aminoglycosides), with 8-fold reductions in the MIC. The same reduction was observed for the extracts of Salvia officinalis and Senna macranthera, which displayed the lowest MIC. Using these combinations resulted in a reduction in the minimum dose required for effective antimicrobial effects, which is interesting because it may decrease both the risk of side effects and the costs of treatment.Item New antineoplastic agent based on a dibenzoylmethane derivative: Cytotoxic effect and direct interaction with DNA(Biophysical Chemistry, 2018-08) Nascimento, Fernanda R.; Moura, Tiago A.; Baeta, Jefferson V.P.B.; Publio, Bruno C.; Ferreira, Pollyanna M.F.; Santos, Anésia A.; França, Andressa A.P.; Rocha, Marcio S.; Diaz-Muñoz, Gaspar; Diaz, Marisa A.N.Melanoma accounts for only 4% of all skin cancers but is among the most lethal cutaneous neoplasms. Dacarbazine is the drug of choice for the treatment of melanoma in Brazil through the public health system mainly because of its low cost. However, it is an alkylating agent of low specificity and elicits a therapeutic response in only 20% of cases. Other drugs available for the treatment of melanoma are expensive, and tumor cells commonly develop resistance to these drugs. The fight against melanoma demands novel, more specific drugs that are effective in killing drug-resistant tumor cells. Dibenzoylmethane (1,3-diphenylpropane-1,3-dione) derivatives are promising antitumor agents. In this study, we investigated the cytotoxic effect of 1,3-diphenyl-2-benzyl-1,3-propanedione (DPBP) on B16F10 melanoma cells as well as its direct interaction with the DNA molecule using optical tweezers. DPBP showed promising results against tumor cells and had a selectivity index of 41.94. Also, we demonstrated the ability of DPBP to interact directly with the DNA molecule. The fact that DPBP can interact with DNA in vitro allows us to hypothesize that such an interaction may also occur in vivo and, therefore, that DPBP may be an alternative to treat patients with drug-resistant melanomas. These findings can guide the development of new and more effective drugs.