Synergistic effect of Lawsonia inermis and Peganum harmala aqueous extracts on in vitro growth of Leishmania tropica promastigotes comparison to Sodium Stibogluconate

Abstract

Promastigotes of genus Leishmania are transmitted by Phlebotomus sandflies bites. Cutaneous leishmaniasis (CL) is endemic in southern parts of Iraq. Lawsonia inermis (henna) leaves contain several active compounds that have antiprotozoal activity, as well as, Peganum harmala possess several alkaloids with antiprotozoal properties. In this study, MTT assay was used to assess the antileishmanial activity of L. inermis and P. harmala aqueous extracts in comparison to pentavalent antimonial drug( sodium stibogluconate) on in vitro promastigotes of Leishmania tropica. L. inermis and P. harmala extracts were prepared in concentrations of (5%, 2.5% and 1.25%) and (10%, 5% and 2.5%) respectively. Also, combinations of various concentrations were prepared to assess the synergistic effect of both plants on promastigotes. Inhibition rate was calculated for each extract concentration and their combinations. Statistical analysis showed a significant(P<0.01) inhibition of promastigotes of L.tropica by both extracts of low and moderate concentrations, while higher concentrations had no inhibitory effect in comparison to sodium stibogluconate solution.. The combination of extracts showed a strong inhibitory effect in comparison to individual extracts of plants. Synergism was obvious when both extracts were combined.