The Efficacy of Ethanol Extract of Lemon verbena on the Skin Infection due to Staphylococcus aureus in an Animal Model

Daily increasing of Staphylococcus aureus resistance to various antibiotics in particular penicillin and Methecilin has led the scientist to look for new medicines in this area. In an in vitro laboratory studies, it has been demonstrated that ethanolic extract of Lemon verbena can prevent the growth of Staphylococcus aureus. In this study the efficacy of ethanolic extract of Lemon verbena against Staphylococcus aureus skin infection were assessed in an in vivo, in animal model. We inoculated 200λ of Staphylococcus aureus suspension with turbidity equal to 0.5 McFarland, interadermally on the shoulder of 63 laboratory 20-30 gram mice. The mice were divided in to 4 groups, 2 control groups: negative(without treatment) and positive (treated with Mupirocin) and 2 test groups that treated for 7 days by ointment prepared from ethanol extract of Lemon verbena (group3), or injection of Lemon verbena solution (group 4). The status of wounds and the rate of recovery was studied, and the presence of local pus after dissection of mice on day 8 recorded and compared with each other. The wound appearance in the second day, on the injection site of S. aureus, in groups1, 4, 3 and 2 were 84.2%, 66.7%, 46.2% and 23.1%, respectively. In the last day, the lesion still was remained in 78.9, 23.1, 92.3 and 77.7% in group 1 -4, respectively. The necrotic and wide wounds were more observed in groups 1 and 3 versus two other groups. The results from this investigation indicated that the ointment prepared from ethanol extract of Lemon verbena is a proper medication to prevent the skin infection by Staphylococcus aureus in the early phase but injected solution of this extract cannot show this effect, and none of them can prevent the wound itself completely.