Antiplasmodial activity of the andiroba (Carapa guianensis Aubl., Meliaceae) oil and its limonoid-rich fraction

Ethnopharmacological relevance: From seeds of Carapa guianensis the Amazon native people extracts the andiroba oil, which is traditionally used as febrifuge, anti-malarial, insecticidal and repellant. The non-saponifiable fraction separated from the oil is rich in limonoids, which assigns its pharmacological effects. Materials and methods: The andiroba oil and its limonoid-rich fraction were submitted to in vitro antiplasmodial bioassay using W-2 and Dd(2) strains of Plasmodium falciparum. The acute toxicity of andiroba oil was evaluated. The limonoid-rich fraction was subjected to fractionation and identified its major constituents. Results: Andiroba oil and its limonoid-rich fraction inhibited the growth of W2 clone in 100%, between 24 and 72 h, at concentrations of 8.2 mu g/mL and 3.1 mu g/mL, respectively. Under the same conditions, the parasitaemia of Dd2 clone provoked by the andiroba oil showed inhibition of 31% (IC50 > 82 mu g/mL) with a time-dependent relationship of 24 h and inhibition of 88% (IC50 8.4 mu g/mL) after 72 h, while for the limonoid-rich fraction the inhibition of Dd(2) clone was 56% (IC50 2.8 mu g/mL) at 24 h and 82% (IC50 0.4 mu g/mL) after 72 h. Andiroba oil in acute toxicity test with a fixed dose (LD50 > 2000 mg/kg) was not toxic The limonoids identified in the oil were gedunin, 6 alpha-acetoxygedunin, 7-deacetoxy-7-oxogedunin, 7-deacetylgedunin, 1,2-dihydro-3 beta-hydroxy-7-deacetoxy-7-oxogedunin and andirobin. Gedunin and derivatives has been reputed as anti-malarials. Conclusion: The results support the traditional use of andiroba oil as antiplasmodial, which additionally proved not to be toxic in bioassays conducted with mice. (C) 2012 Elsevier Ireland Ltd. All rights reserved.