RESUMO

PURPOSE: Bioactive molecules are relevant to fight cancer and associated conditions. Quinoxaline is a privileged N-heterocycle, notably as anticancer agents. Herein, we report the evaluation of the quinoxaline derivatives DEQX and OAQX as anticancer agents, as well as in function of their anti-inflammatory and analgesic activities. METHODS: Quinoxalines were synthesized and tested as anticancer agents based on cell viability and Annexin V-FITC apoptosis. Anti-inflammatory activity was evaluated from mouse carrageenan peritonitis and levels of interleukin (IL)-1ß and tumor necrosis factor (TNF)-alfa for enzyme-linked immunosorbent assay. Hot-plate and acetic acid-induced writing test were employed to investigate analgesia. RESULTS: Both reduced the Ht-29 cell viability in a dependent-concentration manner (p < 0.001). Total apoptosis was detected for cells treated with 12.5 and 25 µg/mL of both the compounds for 24 and 48 h (all doses, p < 0.0001). DEQX (all doses, p < 0.01) and OAQX (all doses, p < 0.001) acted in leukocyte migration and decreased the IL-1ß and TNF-ß levels (p < 0.05). DEQX (all doses, p < 0.05) and OAQX (5mg/kg, p < 0.001) showed peripheral analgesic effect. CONCLUSIONS: In-vitro and in-vivo results suggest that these quinoxalines are promising for application in pharmacological area due to their anticancer, anti-inflammatory, and peripheric analgesia.

Assuntos

Analgésicos , Anti-Inflamatórios , Antineoplásicos , Apoptose , Sobrevivência Celular , Quinoxalinas , Animais , Quinoxalinas/farmacologia , Quinoxalinas/uso terapêutico , Analgésicos/farmacologia , Analgésicos/uso terapêutico , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Antineoplásicos/farmacologia , Camundongos , Apoptose/efeitos dos fármacos , Humanos , Sobrevivência Celular/efeitos dos fármacos , Interleucina-1beta/metabolismo , Fator de Necrose Tumoral alfa/análise , Masculino , Células HT29 , Ensaio de Imunoadsorção Enzimática , Peritonite/tratamento farmacológico

RESUMO

ABSTRACT Purpose: Bioactive molecules are relevant to fight cancer and associated conditions. Quinoxaline is a privileged N-heterocycle, notably as anticancer agents. Herein, we report the evaluation of the quinoxaline derivatives DEQX and OAQX as anticancer agents, as well as in function of their anti-inflammatory and analgesic activities. Methods: Quinoxalines were synthesized and tested as anticancer agents based on cell viability and Annexin V-FITC apoptosis. Anti-inflammatory activity was evaluated from mouse carrageenan peritonitis and levels of interleukin (IL)-1β and tumor necrosis factor (TNF)-alfa for enzyme-linked immunosorbent assay. Hot-plate and acetic acid-induced writing test were employed to investigate analgesia. Results: Both reduced the Ht-29 cell viability in a dependent-concentration manner (p < 0.001). Total apoptosis was detected for cells treated with 12.5 and 25 µg/mL of both the compounds for 24 and 48 h (all doses, p < 0.0001). DEQX (all doses, p < 0.01) and OAQX (all doses, p < 0.001) acted in leukocyte migration and decreased the IL-1β and TNF-β levels (p < 0.05). DEQX (all doses, p < 0.05) and OAQX (5mg/kg, p < 0.001) showed peripheral analgesic effect. Conclusions: In-vitro and in-vivo results suggest that these quinoxalines are promising for application in pharmacological area due to their anticancer, anti-inflammatory, and peripheric analgesia.

RESUMO

The acidity of organic compounds is highly relevant to understanding several biological processes. Although the relevance and challenges in estimating pKa values of organic acids is recognized by several reported works in the literature, there is a lack in determining the acidity of amides. This paper presents an experimental/theoretical combined investigation on the acid dissociation of the compound 6,7-dinitro-1,4-dihydroquinoxaline-2,3-dione (DNQX), a well-established antagonist of ionotropic glutamate receptor GluA2. DNQX was synthesized, and its two acidic constants were determined by UV-vis spectroscopy. The experimental pKa of 6.99 ± 0.02 and 10.57 ± 0.01 indicate that DNQX mainly exists as an anionic form (DNQXA1) in physiological media, which was also confirmed by 1H NMR analysis. Five computational methods were applied for estimating the theoretical pKa values of DNQX, including B3LYP, M06-2X, ωB97XD, and CBS-QB3, which were able to provide reasonable estimates for pKa associated with DNQX. Molecular dynamics studies have demonstrated that DNQXA1' binds more effectively to the pocket of the GluA2 than neutral DNQX, and this fact is coherent to the interactions between amidic oxygens and Arg845 being the main interactions of this host-guest system. Moreover, interaction of GluA2 with endogenous glutamate is stronger than that with DNQXA1, which is in agreement with literature. To the best of our knowledge, we report herein an unprecedented approach involving acidity of the antagonist DNQX, as well as the possible implications in binding to GluA2.