Inhibition of pain and inflamation induced by formalin in male mice by ethanolic extract of saffron (Crocus sativus) and its constituents; crocin and safranal

Previous investigations have confirmed the anti-inflammatory and analgesic effects of aqueous-ethanol extract of saffron on formalin induced pain in small male mice. Since there is difference between ethanol and aqueous-ethanol extract of saffron, this study was performed in order to evaluate the effect of ethanol saffron extract on acute and chronic pain in small male mice.

This experimental study was performed on male NMRI mice which weighed 20-25 grams (6 in each test). Drugs were administered 30 minutes before 2% formalin solution injection. Then the animals were evaluated for 60 minutes in 5 minutes intervals. Inflammation was investigated in minute 25 by Mercury immersion method. Data were analyzed with one way variance analysis and Tukey's test by SPSS 9.01 software.

Ethanol saffron extract showed anti-nociceptive effect in 5 mg/kg dose for acute phase and in 10 mg/kg dose for chronic phase. Naloxane, Dextromethorphan and L-NAME inhibited the extract action in acute phase as well as chronic phase. Safranal showed anti-nociceptive effect in acute phase and Crocin in chronic phase. Saffron extract with dose of 2.5, 5 and 10 mg/kg controlled inflammation 30%, 66% and 80% respectively, but Safranal and Crocin didn’t show a similar effect.

Ethanol extract of C sativus exerts its effect on the acute phase of formalin test, which is possibly caused by Safranal. Probable stimulation of opioid, NMDA glutamatergic and nitric oxide dependent pathways leads to pain inhibition in acute and chronic phases.