Natural compounds and extracts from Mexican medicinal plants with anti-leishmaniasis activity: An update

Leishmaniasis is considered as an emerging, uncontrolled disease and is endemic in 98 countries. Annually, about 2 million cases of cutaneous and 500 000 cases of visceral-type leishmaniasis are recorded and 60 000 persons died from the disease. In Mexico, cutaneous leishmaniasis is known as chiclero's ulcer and is reported in 22 states, it is considered as a health problem. For its treatment, pentavalent antimonial drugs are administered. These drugs cause severe side effects, are costly. Drug-resistant cases have been reported and have been developing for over 70 years. One alternative to the drugs that are currently available is to find active molecules in medicinal plants. Dihydrocorynantheine, corynantheine and corynantheidine are active against Leishmania major, while harmane, pleiocarpin, buchtienin, luteolin and quercetin are active against Leishmania donovani. In Mexico, about 20 medicinal plants have been evaluated against Leishmania mexicana, among which the most active are Tridax procumbens, Lonchocarpus xuul and Pentalinon andrieuxii. From these plants, active compounds with IC50 <= 30 mg/mL or mM have been isolated, such as 3(S)-16,17-didehydrofalcarinol or Oxylipin, cholestra-4,20,24-trien-3-one or pentalinosterol, 24-methylcholest-4-24(28)-dien-3-one, cholest-4-en-3-one,6,7-dihydroneridie-none, neridienone, cholest-5,20,24-trien-3b-ol, and isocordoin. Today, only pentalinonsterol has been synthesized and assayed in the visceral leishmaniasis experimental model using BALB/c mice infected with Leishmania donovani. Liposome formulation of this compound administered by intravenous route at 2.5 mg/kg showed a significant reduction of parasite load in mouse liver and spleen.