Black cumin seed essential oil, as a potent analgesic and antiinflammatory drug

The steam-distilled essential oil of Iranian black cumin seed (Nigella sativa L.) was investigated for its composition and analgesic and antiinflammatory properties. After oil analysis by GC/MS, 20 compounds were identified in the oil, obtained in 0.4% (v/w) yield. Among them, para-cymene (37.3%) and thymoquinone (13.7%) were the major components. Acetic acid-induced writhing, formalin and light tail flick tests were used for assessment of analgesic activity. Antiinflammatory activity was evaluated using carrageenan-induced paw oedema in rats and croton oil-induced ear oedema in mice. Black cumin seed essential oil (BCSEO) was found to produce a significant analgesic effect in acetic acid-induced writhing, formalin and light tail flick tests. Naloxone, an opioid antagonist, could not reverse the analgesic effect observed in the formalin test. Although oral administration of BCSEO at doses of 100, 200 and 400 micro L/kg did not exert a significant antiinflammatory effect in the carrageenan test, i.p. injection of the same doses significantly (p < 0.001) inhibited carrageenan-induced paw oedema. BCSEO at doses of 10 and 20 micro L/ear could also reduce croton oil-induced oedema. It seems that mechanism(s) other than opioid receptors is (are) involved in the analgesic effect of BCSEO since naloxone could not reverse this effect. Both systemic and local administration of BCSEO showed antiinflammatory activity. Thymoquinone, as one of the major components of BCSEO, probably has an important role in these pharmacological effects.