RESUMO
Croton linearis Jacq. is an aromatic shrub that has been utilized in traditional medicine in the Bahamas, Jamaica, and Cuba. Recent studies have revealed the antiprotozoal potential of its leaves. The present work is aimed to identify the volatile constituents of essential oil from the stems of C. linearis (CLS-EO) and evaluate its in vitro antileishmanial activity. In addition, an in silico study of the molecular interactions was performed using molecular docking. A gas chromatographic-mass spectrometric analysis of CLS-EO identified 1,8-cineole (27.8%), α-pinene (11.1%), cis-sabinene (8.1%), p-cymene (5.7%), α-terpineol (4.4%), epi-γ-eudesmol (4.2%), linalool (3.9%), and terpinen-4-ol (2.6%) as major constituents. The evaluation of antileishmanial activity showed that CLS-EO has good activity on both parasite forms (IC50Promastigote = 21.4 ± 0.1 µg/mL; IC50Amastigote = 18.9 ± 0.3 µg/mL), with a CC50 of 49.0 ± 5.0 µg/mL on peritoneal macrophages from BALB/c mice (selectivity index = 2 and 3 using the promastigote and amastigote results). Molecular docking showed good binding of epi-γ-eudesmol with different target enzymes of Leishmania. This study is the first report of the chemical composition and anti-Leishmania evaluation of CLS-EO. These findings provide support for further studies of the antileishmanial effect of this product.
RESUMO
There is an urgent need to discover and develop new drugs to combat parasitic diseases as Chagas disease (Trypanosoma cruzi), sleeping sickness (Trypanosoma brucei), and leishmaniasis (Leishmania ssp.). These diseases are considered among the 13 most unattended diseases worldwide according to the WHO. In the present work, the synthesis of 14 arylsubstituted imidazoles and its molecular docking onto sterol 14α-demethylase (CYP51) was executed. In addition, the compounds, antiprotozoal activity against T. brucei, T. cruzi, Trypanosoma brucei rhodesiense, and Leishmania infantum was evaluated. In vitro antiparasitic results of the arylsubstituted imidazoles against T. brucei, T. cruzi, T.b. rhodesiense, and L. infantum indicated that all samples from arylsubstituted imidazole compounds presented interesting antiparasitic activity to various extent. The ligands 5a, 5c, 5e, 5f, 5g, 5i, and 5j exhibited strong activity against T. brucei, T. cruzi, T.b. rhodesiense, and L. infantum with IC50 values ranging from 0.86 to 10.23 µM. Most samples were cytotoxic against MRC-5 cell lines (1.12 < CC50 < 51.09 µM) and only ligand 5c showed a good selectivity against all tested parasites. According to the results of the molecular docking, the aromatic substituents in positions 1, 4, and 5 have mainly stabilizing hydrophobic interactions with the enzyme matrix, while the oxygen from NO2, SO3H, and OH groups interacts with the Fe2+ ion of the Heme group.