Therapeutic Effect of Scrophularia striata Ethanolic Extract against Localized Cutaneous Leishmaniasis Caused by Leishmania major (MRHO/IR/75/ER)

Background: We evaluated the effect of the ethanolic extract of Scrophularia striata on the Iranian strain of Leishmania major (MRHO/IR/75/ER) both in vitro and in vivo conditions.

Methods: The effective dose (ED) of ethanolic extract of S. striata were determined using MTT assay on the growth of promastigote forms of L. major in axenic culture media. Then, the ED₅₀ of S. striata on mice peritoneal macrophages was determined using calculation of amastigote forms on mice peritoneal macrophages. For in vivo experiments, the therapeutic effects of various concentrations of S. striata on infected BALB/c mice was studied. A total of 75 infected mice were randomly divided into five groups: two groups (10% and 50% of S. striata) as experimental and three as control (ethanol 50%, Glucantime® and no treatment). The efficacy were determined by comparing the diameters of lesions and the microscopically examinations.

Results: The effect of S. striata extract (0/625%, 1/25%, 2/5%, 5%, 10%, 20% and 50%) on peritoneal macrophages of Balb/c mice infected with L.major in tissue-culture slides was assessed. S. striata extract (10%) removed the L.major amastigotes-infected macrophages significantly after 24 h (P < 0.05). The higher concentrations of S. striata ethanolic extract (20%, and 50%) had highly toxic effects on macrophages, resulted in the disintegration of the cytoplasm of macrophages after 48 and 72 h. In concentration 10% of S. striata, more than 85% of L. major amastigotes-infected macrophages were damaged without cytotoxicity effects on macrophages. The higher concentrations had toxic effects on cultured macrophages.

Conclusion: S. striata ethanolic extract 10% had anti leishmanial effects in both in vivo and in vitro.