LAUSR

The present study assessed the 2,3-substituted-1,3-thiazolidin-4-ones antinociceptive potential looking at the acute nociception model induced by thermal stimulation in mice. This was done to contribute to the development of new analgesic drugs, in addition to the fact that 4-thiazolidinones are an important scaffold associated with many pharmacological activities. The synthesized compounds were characterized by GC-MS and NMR of 1H and 13C and administered at a dose of 100 mg/kg hydrochloride salt (ip). Sodium dipyrone (250 and 500 mg/Kg; ip) and tramadol hydrochloride (25 and 50 mg/Kg; ip) were used as positive controls. The hot plate test was done at a temperature of 50 ± 0.1 °C and animals assessed at 30, 60, and 90 min after the drugs were administered. Among the fourteen compounds tested, nine (5Aa, 5Ab, 5Ac, 5Ad, 5Ba, 5Bb, 5Bd, 5Ea, and 5Fa) showed significant increases in latency time when compared to saline (negative control) and compared to sodium dipyrone (500 mg/Kg; ip) in a 30-min assessment. The highest latency times were obtained for 3-(2-piperidin-1-yl)ethyl)thiazolidin-4-one derivatives (5Ab, 5Ac, and 5Ad). This highlights three findings about the chemical structure that improve activity: (i) an ethylenic link; (ii) a six-membered piperidine; (iii) an aliphatic substituent at the 2-position of thiazolidinone ring.