A Review of the Effects of Herbal Medicines on Leishmaniasis

Leishmaniasis is a tropical mistreated sandfly-borne contagion caused by hemoflagellate protozoa of the Leishmania species and it is endemic in many countries such as Iran, Afghanistan, Syria, Saudi Arabia, Brazil, and Peru. After malaria, leishmania spp. causes the highest rates of mortality and morbidity. Several major risk factors are involved in the spread of leishmaniasis such as drug resistance, environmental changes, HIV epidemic, inadequate vector control and migration of non-immune individuals to endemic areas. Leishmaniasis is a disease with diverse clinical manifestations that depends on both infecting species of Leishmania and the immune response of the host. Different forms of the disease include cutaneous, mucocutaneous and visceral forms. The most dangerous form is Visceral Leishmaniasis (VL) which can be fatal among untreated patients. The availability of the inadequate number of antileishmanial chemotherapeutic compounds, high-cost treatment, rising drug resistance as well as severe toxicities of the drugs obscures the treatment of VL. Many investigations showed antileishmanial activity of herbal extracts or chemical derivatives from natural sources in vitro against promastigote and amastigote forms or in vivo against Leishmania-infected animals. A review of related studies revealed that herbal extracts demonstrating antileishmanial activities in vivo or in vitro alone or combined with suggested drugs seem to confirm their use in folk medicine. Additionally, the antileishmanial activity of more than a hundred plants have been recognized in this regard.  It is worth noting that plants are notable sources of medicine production, because of their long association with parasites.