Abstract

 The present study was designed to investigate the antinociceptive activity of the watery suspension of powdered Nigella sativa seeds in mice. The antinociceptive effect of the watery suspension of Nigella sativa seeds compared with that of Naproxen was evaluated by formalin test in which the stimulus is standardized and measures potency and duration of response. In this test, however, Nigella sativa seeds watery suspension significantly (P<0.05) reduced nociceptive reaction both at early and late phases whereas, Naproxen attenuated the nociceptive response in late phase of test only. Pre-treatment with Naloxone (1 mg / kg B.W.IM.) significantly (P<0.05) reversed the analgesic effect of Nigella seeds at late phase only. This may implicate an opioid activity of Nigella seeds constituents (particularly thymoquinone) participating in its analgesic activity which characterized by inhibitory effect on nociceptive system and / or inflammatory mediators.