Antinociceptive Effects of Hydro-Alcoholic Extract of Scrophularia striata Boiss using Formalin

Background and Objective: Nowadays, a wide variety of chemical agents are used to mitigate the pain, whereas all of them are associated with complications. Scrophularia striata Boiss that grows in the area of Ilam in Iran has been experimentally used in the treatment of various diseases. However, there is a lack of research on this plant. This study was an endeavor to elucidate the effect of hydro-alcoholic extract of Scrophularia striata Boiss on formalin-induced pain. Materials and Methods: In this study, 40 male mice (25-30 g) were randomly selected and divided into five groups of 8 including a control group (receiving saline) along with 4 treatment groups (receiving the extract doses of 150, 300, 600 and 900 mg/kg). 30 minutes after IP administration with saline (in the control group), and different doses of extract (in the treatment groups), animals were immediately transferred to a special cage and after formalin injection in their paw skin, induced pain behaviors were recorded for 60 minutes. Results: As the dosage of extract increased, significant reductions were seen in phases 1 and 2 in the treatment groups rather than control group. But, there was not any change in interphase. Extract administration with doses of 150, 300, 600 and 900 mg/kg caused significant reduction in nociceptive behaviors in the first phase of formalin test. Also, this decreasing pattern was seen in phase 2 in 600 and 900 mg/kg treatment groups. Despite an evident decrease in nociceptive behaviors in the interphase, it was nonsignificant. Conclusion: This study illustrates that Scrophularia striata Boiss hydroalcoholic extract has analgesic properties on formalin test in mice.