Evaluation of Larvicidal and in Vitro. Antiparasitic Activities of Plants in a Biodiversity Plot in the Altos de Campana National Park, Panama

Abstract

This TDR/WHO project was carried out from 2003 to 2005 in an 0.1-ha biodiversity plot in the Altos de Campana National Park to discover novel active antiparasitic and larvicidal compounds in Panamanian plants. One-hundred-fifty organic plant extracts representing 43 families, 73 genera, and 93 species were tested in a panel of antimalarial (Plasmodium falciparum. W2, chloroquine resistant), antileishmanial (Leishmania mexicana. amastigotes), antitrypanosomal (Trypanosoma cruzi. trypomastigotes), and larvicidal (Aedes aegypti.) screens. Of these 150 plant extracts, two (1.3%) (Talisia nervosa. and Topobea parasitica.) showed significant antimalarial activity (IC₅₀ values < 10 µg/ml), two (1.3%) (Cestrum megalophyllum. and Zanthoxylum acuminatum.) weak antileishmanial activity (IC₅₀ values ranging from 10 to 20 µg/ml), one (0.6%) (Zanthoxylum acuminatum.) weak antitrypanosomal activity (IC₅₀ values ranging from 10 to 20 µg/ml), and one (0.6%) (Piper fimbriulatum.) larvicidal activity (LC₁₀₀ values < 30 µg/ml). Ethyl gallate (1) and methyl gallate (2) were isolated from stems of Talisia nervosa. by bioassay-guided fractionation. Both (1) and (2) showed weak in vitro. antiplasmodial activity against P. falciparum. (IC₅₀ 35.3 µM and IC₅₀ 38.0 µM, respectively), but both compounds were less active than chloroquine (IC₅₀ 0.088 µM). Moreover, compounds (1) (IC₅₀ 33.1 µM) and (2) (IC₅₀ 33.6 µM) showed weakly antileishmanial activity (miltefosine: IC₅₀ 0.5 µM), but they were not cytotoxic to Vero mammalian cells.

Keywords:

• Antileishmanial
• antimalarial
• antitrypanosomal
• biodiversity plot
• larvicidal
• Panama