Banca de QUALIFICAÇÃO: RYERTSON NOGUEIRA DA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : RYERTSON NOGUEIRA DA SILVA
DATA : 14/06/2019
HORA: 09:00
LOCAL: A definir
TÍTULO:

Evaluation of cytotoxic and antimicrobial activities of quinoxalin derivatives in microemulsion systems

PALAVRAS-CHAVES:

Quinoxaline, microemulsion, delivery, DPDNQX, biological activity

PÁGINAS: 75
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Orgânica
ESPECIALIDADE: Síntese Orgânica
RESUMO:

Quinoxalines are nitrogen-containing heterocyclic compounds with numerous technological and biological properties described in the literature, but their applicability in therapy is restricted because of their low solubility in water and, consequently, their low oral bioavailability. Microemulsions (ME) are systems that allow the solubilization of substances of different polarities, accentuating their bioavailability, absorption, stability and reducing the toxicity of incorporated drugs. Therefore, the objective of this work is the synthesis of a quinoxaline derivative and the use of a microemulsion formulation for the incorporation and evaluation of the antioxidant, antimicrobial and antitumor properties of this derivative. Before and after its incorporation, the formulation was characterized physicochemically through the techniques of electrical conductivity, pH, polydispersity index, surface tension and dynamic light scattering (DLS). The 2,3-diphenyloxy-6,7-dinitro-quinoxaline derivative was synthesized by nucleophilic aromatic substitution reaction and characterized by Nuclear Magnetic Resonance. The antioxidant evaluation was done using the free radical scavenging method DPPH and ABTS assay, while the total antioxidant capacity was determined by the phosphomolybdenum method. The antitumor activity was performed by the MTT assay, while the antimicrobial activities were evaluated by the Minimum Inhibitory Concentration (MIC). The developed microemulsion system consists of 45% distilled water, 50% of Labrasol® and 5% of isopropyl myristate, giving direct micelle, where 0.17% w / w of DFDNQX was incorporated. The pH of the formulation after incorporation of the compound is 4.71, suitable for application to humans, by oral administration. The conductivity was 20.35 μS / cm and is suitable for micellar oil-in-water system, besides suggesting an isotropic behavior. The size of the hydrodynamic diameter of the micelles was 562.06 nm, satisfactory for this type of system. The polydispersity index was 0.242, while the zeta potential was -12.2 mV, indicating good system stability. The antioxidant evaluation values of the molecule via DPPH assay are IC 50 = 51.78 μg / mL and IC 50 = 91.37 μg / mL in the microemulsion and isolated, respectively; while with trolox it is IC50 = 48.12 μg / mL. Values via ABTS are IC 50 = 128.35 μg / mL in the microemulsion, IC 50 = 195.49 μg / mL isolated and IC 50 = 102.18 μg / mL with trolox. Indicating that the microemulsion potentiated the activity. The antibacterial evaluation values had MIC of 8 μg / mL and 16 μg / mL in the microemulsion and isolated, respectively; while tetracycline was 1 μg / mL. The antifungal activity values were 8 μg / mL and 64 μg / mL in the microemulsion and isolated; while fluconazole was 16 μg / mL. The antitumor activity values in the HL-60 strain were IC50 = 23.4 μg / mL and 36.5 μg / mL; while cisplatin was IC50 = 27.3 μg / mL. And the values for HaCat were IC50 = 394.79 μg / mL and IC50 = 287.49 μg / mL in the microemulsion and isolated, respectively; while cisplatin was IC 50 = 16.73 μg / mL. Microemulsions presented higher potential than the isolated molecule in all biological tests.

MEMBROS DA BANCA:
Externo ao Programa - 1789788 - ADLEY ANTONINI NEVES DE LIMA
Interno - 1753094 - ALCIDES DE OLIVEIRA WANDERLEY NETO
Presidente - 1569526 - RENATA MENDONÇA ARAUJO