Natural Compounds and Extracts from Mexican Medicinal Plants with Anti-Leishmanial Activity: An Update

Abstract

Leishmaniasis is considered 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 die from the disease. In Mexico, cutaneous leishmaniasis is known as chiclero's ulcer and is reported in 22 states; it is considered a health problem. For its treatment, pentavalent antimonial drugs are administered; these drugs cause severe side effects, are costly, and drug-resistant cases have been reported and have been developing for >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 L. donovani. In Mexico, about 20 medicinal plants have been evaluated against L. mexicana, among which the most active are Tridax procumbens, Tridax procumbens, Pentalinon andrieuxii, Lantana camara, Schinus molle, and Prosopis laevigata. From some of these plants, active compounds with IC 50 ≤ 30 μg/mL or μM 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-dihy-droneridie-none, neridienone, cholest-5,20,24-trien-3β-ol, and isocordoin. Today, the only pentalinonsterol has been synthesized and assayed in the visceral leishmaniasis experimental model using BALB/c mice infected with L. 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.