Antinociceptive and anti-inflammatory effect of alcoholic extract of root and stem of Scrophularia striata Boiss. in male mice

Some plants are used in traditional medicine as analgesic drugs. The aim of this study was investigation of antinociceptive and anti-inflammatory effect of hydroalcoholic extract of Scrophularia striata Boiss. in male mice. This plant has been traditionally used as an analgesic drug by people of Zagros. In this research, 224 NMRI male mice weighting 25 ± 35 g were used. In inflammation test, animals were divided into 7 groups including control, positive control (receiving 15 mg/kg dexamethasone) and 5 groups received hydroalcoholic extract of root and stem of Scrophularia striata (200, 400, 500, 600, 800 mg/kg). Xylene was used for inflammation induction. Formalin test was used for investigation of antinociceptive effect of the extract. In antinociception test, animals were divided into 7 groups including, positive control (receiving 10 mg/kg morphine), control treatment and 5 groups received hydroalcoholic extract of root and stem of Scrophularia striata (200, 400, 500, 600, 800 mg/kg). Injections were performed intraperitoneally. Results showed that alcoholic extract of root and stem of Scrophularia striata significantly decreased inflammation at doses of 600 and 800 mg/kg (p < 0.001). Also, hydroalcoholic extract of root and stem of Scrophularia striata decreased nociception in both 1st and 2nd phase of formalin test. The maximum effect was observed at doses of 600 and 800 mg/kg (p < 0.001). Consequently, it seems that anti-inflammatory and antinociceptive effects of the extract of root and stem of Scrophularia striata are due to flavonoids especially quercetin that inhibit lipooxygenase, phospholipase A2 and nitric oxide synthase.