Leishmanicidal Evaluation of Stizophyllum perforatum and Isolated Compounds.

Stizophyllum perforatum (Cham.) Miers belongs to the Bignoniaceae family and comprises approximately 113 genera and 800 species, widely distributed in the tropical regions of South America and Africa, where they occur as shrubs, trees, and lianas.1 The genus Stizophyllum is used in folk medicine to treat throat and nose ailments.2 This work aimed to evaluate the leishmanicidal activity of S. perforatum leaves crude extract and the isolation of bioactive compounds. The leaves material was extracted with ethanol by maceration, providing 31 g of crude extract. The extract was then subjected to the bioassay with promastigote forms of Leishmania amazonensis (MHOM/BR/PH8), and the inhibition of cell growth was determined by counting cells in a Neubauer chamber, the positive and negative controls were amphotericin B and 0.1% dimethylsulfoxide (DMSO), respectively. The leaf extract showed an IC50 (50 % inhibitory concentration) of 6.06 ± 2.82 µg/mL, showing that the extract was very promising for the promastigote form of L. amazonensis. The crude extract was submitted to liquid-liquid partition, and the bioactive EtOAc fraction was fractionated by Sephadex LH-20 furnishing compound 1 (fractions 53-54, 81 mg). Also, part of the EtOAc fraction was purified by solid-phase extraction into four subfractions. The bioactive fraction 3 was subjected to column chromatography with silica and mobile phase gradient of CHCl3-CH3OH. Subfractions 6-12 (103 mg) and 13-25 (64 mg) were then purified by preparative RP-HPLC, mobile phase CH3OH-H2O 90:10 (v/v), flow 5 mL/min and detection at 220 nm. Subfraction 6-12 provided compounds 2 (7 mg), 3 (14 mg), 4 (22 mg) and 5 (3 mg). Subfraction 13-25 also resulted in the isolation of compound 2 (64 mg). The isolated compounds were identified by NMR data. Further studies are in progress to isolate other compounds and also to evaluate the biological activity of the identified compounds.