Antinociceptive activity of a new benzofuranone derived from a chalcone.

Chalcones represent an important group of natural or synthetic compounds with a variety of biological activities including antinociceptive and anti-inflammatory ones. The aim of this work was the synthesis of a new benzofuranone compound and evaluation of its antinociceptive potential in mice. The new benzofuranone 4 was synthesized from chalcone 3. The antinociceptive activity of 4 was determined by writhing, formalin, capsaicin, and glutamate and hot-plate tests. Compound 4 caused potent and dose-related inhibition against the writhing test with ID₅₀ 6.1 (5.1-7.6) μmol/kg, i.p., being about 15 times more active than the reference drugs, acetyl salicylic acid and acetaminophen. It was also effective in a dose-dependent manner in significantly reducing the painful stimulus in both phases of formalin, in the capsaicin and in the glutamate test with ID₅₀ values of 27.3 (24.5-30.6) and 18.9 (18.5-19.4) μmol/kg (first and second phase), 12.6 (9.8-16.2) and 24.5 (20.4-29.6) μmol/kg respectively. The results showed that the studied compound exhibits both central and peripheral antinociceptive activities and might be further used as a model to obtain new and more potent analgesic drugs.