RESUMEN
A series of 3,4-diaryl-1,2,5-oxadiazoles and 3,4-diaryl-1,2,5-oxadiazole N-oxides were prepared and evaluated for COX-2 and COX-1 binding affinity in vitro and for antiinflammatory activity by the rat paw edema method. p-Methoxy (p-OMe) substituted compounds 9, 21, 34, 41, 42 showed COX-2 enzyme inhibition higher than that showed by compounds with other substituents. 3,4-Di(4-methoxyphenyl)-1,2,5-oxadiazole N-oxide (42) showed COX-2 enzyme inhibition of 54% at 22 micromol L(-1) and COX-1 enzyme inhibition of 44% at 88 micromol L(-1) concentrations, but showed very low in vivo anti-inflammatory activity. Its deoxygenated derivative (21) showed lower COX-2 enzyme inhibition (26% at 22 pmol L(-1)) and higher COX-1 enzyme inhibition (53% at 88 micromol L(-1)) but, marked in vivo anti-inflammatory activity (71% at 25 mg kg(-1)) vs. celecoxib (48% at 12.5 mg kg(-1)). Molecular modeling (docking) studies showed that the methoxy group is positioned in the vicinity of COX-2 secondary pocket and it also participates in hydrogen bonding interactions in the COX-2 active site. These preliminary studies suggest that p-methoxy (p-OMe) group in one of benzene rings may give potentially active leads in this series of oxadiazole/N-oxides.
Asunto(s)
Inhibidores de la Ciclooxigenasa 2/síntesis química , Inhibidores de la Ciclooxigenasa 2/farmacología , Oxadiazoles/síntesis química , Oxadiazoles/farmacología , Animales , Carragenina , Ciclooxigenasa 2/química , Edema/inducido químicamente , Edema/prevención & control , Pie/patología , Espectroscopía de Resonancia Magnética , Masculino , Modelos Moleculares , Óxidos , Ratas , Ratas Sprague-Dawley , Espectrofotometría Infrarroja , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
It was envisaged to combine high antipyretic activity of paracetamol into commonly used NSAIDs. To achieve this goal new chemical entities were synthesized by chemically combining paracetamol and NSAIDs, and biologically evaluated for their antipyretic, analgesic, anti-inflammatory and ulcerogenic potential. The acid chloride of parent NSAIDs was reacted with excess of p-aminophenol to yield the desired p-amidophenol derivatives (1B-7B). Acetate derivatives (1C-7C) of these phenols (1B-7B) were also prepared by their treatment with acetic anhydride, in order to see the impact of blocking the free phenolic group on the biological activity of the derivatives. All the synthesized p-amidophenol derivatives showed improved antipyretic activity than paracetamol with retention of anti-inflammatory activity of their parent NSAIDs. These compounds elicited no ulcerogenicity unlike their parent drugs.