Analgesic and Anti-Inflammatory Effects of Hydroalcoholic Extract of Stachys Lavandulifolia Vahl s, Aerial Parts in Male Mice

Introduction & In recent years, investigations on different species of Stachys have shown that extracts or components of this species exert various pharmacological effects including anti-inflammatory, antitoxic, antibacterial, antioxidant and cytotoxic effects. The aim of this study was to investigate the analgesic and anti-inflammatory effects of the aerial parts of the hydroalcoholic extract of Stachys lavanduifolia Vahl in male mice. In this experimental study which was conducted at Payam-e-Noor and Shahid Beheshti Medical University in 2009-2010, the analgesic effects of Stachys lavanduifolia Vahl in mice were studied, using the formalin and tail immersion tests. Also, the anti-inflammatory effects of this plant was studied in mice, using xylene-induced ear edema. Male NMRI mice, weighing, 20-25 g, were assigned into five groups: negative control (received 0.5% of aqueous solution of Tween 20), positive control in formalin test (received morphine, 10 mg/kg), positive control in xylene test (received dexamethason 15 mg/kg), and experimental groups. Experimental groups were intraperitoneally injected by 100, 200 and 400 mg/kg of hydroalcoholic extracts of Stachys lavanduifolia Vahl. Data were analyzed using SPSS software using ANOVA and post hoc Tukey test. Results showed that all doses of Stachys lavandulifolia extract (100, 200 and 400 mg/kg), significantly (p<0.001) reduced the licking time in experimental groups, both in acute and chronic phases of formalin test, compared to the control groups. In the hot water tail immersion test, the hydroalcoholic extracts of the plant (200 and 400 mg/kg) showed maximum inhibitory effect in the xylene test. Moreover, all doses of extracts significantly inhibited (particularly the extracts at dose of 400 mg/kg) the xylene-induced ear edema. There was no significant difference with positive control group in this dose. Findings of this study suggested that the extract of Stachys lavandulifolia have analgesic and anti-inflammatory effects.