Carapa guianensis Aublet (Andiroba) Seed Oil: Chemical Composition and Antileishmanial Activity Limonoid-Rich Fractions

Leishmaniasis is a complex of diseases caused by protozoa of the genus Leishmania and affects millions of people around the world. Several species of plants are used by traditional communities for the treatment of this disease, among which is Carapa guianensis Aubl. (Meliaceae), popularly known as andiroba. The objective of the present work was to conduct a chemical study of C. guianensis seed oil and its Ihnonoid-rich fractions, with the aim of identifying its secondary metabolites, particularly the limonoids, in addition to investigating its anti-Leishmania potential. The chemical analyses of the C. guianensis seed oil and fractions were obtained by electrospray ionization mass spectrometry (ESI-MS). The cytotoxic activity was tested against peritoneal macrophages, and antileishmanial activity was evaluated against promastigotes and intracellular amastigotes of Leishmania amazonensis. All the C. guianensis seed oil samples analyzed exhibited the same pattern of fatty acids, while the limonoids 7-deacetoxy-7-hydroxygedunin, deacetyldihydrogedunin, deoxygedunin, andirobin, gedunin, 11 beta-hydroxygedunin, 17-g,lycolyldeoxygedunin, 6 alpha-acetoxygedunin, and 6 alpha,11 beta-diacetoxygedunin were identified in the limonoid-rich fractions of the oil. The C. guianensis seed oil did not exhibit antileishmanial activity, and cytotoxicity was higher than 1000 mu g/mL. Three limonoid-rich oil fractions demonstrated activity against promastigotes (IC50 of 10.53 +/- 0.050, 25.3 +/- 0.057, and 56.9 +/- 0.043 mu g/mL) and intracellular amastigotes (IC50 of 27.31 +/- 0.091, 78.42 +/- 0.086, and 352.2 +/- 0.145 mu g/mL) of L. amazonensis, as well as cytotoxicity against peritoneal macrophages (CC50 of 78.55 +/- 1.406, 139.0 +/- 1.523, and 607.7 +/- 1.217 mu g/mL). The anti-Leishmania activity of the limonoid-rich fractions of C. guianensis can be attributed to the limonoids 11 beta-hydroxygedunin and 6 alpha,11 beta-diacetoxygedunin detected in the chemical analysis.