In vitro and in vivo toxicological study of the Pterodon pubescens seed oil

The oil of Pterodon pubescens seeds (PpSO) is known for its cercaricidal and anti-inflammatory effects. Its anti-rheumatic activity was recently reported using mice with collagen II-induced arthritis treated with a hydroalcoholic extract of PpSO, mimicking the wine infusion used in popular medicine. In the present study, PpSO was tested for acute toxicity, mutagenic activity and cytotoxicity for human peripheral blood mononuclear cells (PBMNC). PpSO was obtained after seed extraction with 100% ethanol and evaporation. Cytotoxicity was estimated using the tetrazolium salt reduction test (MTT assay) by PBMNC (2.5 x 10(5) cells/ml) after exposure to 0.07, 0.7 and 7 microg PpSO/ml for 24 and 48 h. In the mutagenesis assay, the Salmonella/mammalian microsome assay was employed with or without metabolization. Acute toxicity was studied on 30 (n = 10/group) male DBA1/J mice (20 +/- 2 g) after a single oral dose of 2, 4, and 8 g PpSO/kg b.w. The animals were observed for 24 h, anesthetized, sacrificed and autopsied. The organs were processed for histopathology by staining with hematoxylin-eosin. The IC50 of PpSO to PBMNC in RPMI 1640 supplemented with 5% fetal calf serum (FCS) was 2 and 1 microg PpSO/ml after 24 and 48 h, respectively. The mutagenic test performed with or without metabolic activation of PpSO did not show mutagenic activity for the concentrations tested (7 and 70 microg/ml). Mouse mortality or significant signs of acute toxicity (ocular, cardiovascular, gastrointestinal, motor or respiratory signs) for the PpSO doses tested was not observed. The organs did not show any macroscopic alterations. Histopathologic analysis of the tissues also did not demonstrate any lesions. The present study provides data to classify PpSO as non-cytotoxic to PBMNC, non-mutagenic, and non-toxic after acute administration since the PpSO doses tested were extremely higher than those used by the population.