RESUMEN
The QSAR study of 34 2-aryl-naphthoimidazoles screened so far revealed that σi is the most important factor for their lytic activity on the bloodstream trypomastigote forms of T. cruzi, the etiologic agent of Chagas disease. Based on this result, 16 new N-alkyl-naphthoimidazoles derived from 6,6-dimethyl-3,4,5,6-tetrahydrobenzo[7,8]chromene[5,6-d]imidazole (the product of the reaction of ß-lapachone with paraformaldehyde) by its reaction with halo-alkanes were prepared and evaluated against the parasite and peritoneal macrophages. The N1-n-hexyl and N3-n-hexyl naphthoimidazoles were 2.2 and 3.2 times more active than the standard drug benznidazole with selectivity indices of 2.7 and 13.4, respectively.
RESUMEN
As part of our search of bioactive saponins from Brazilian plants, phytochemical study of the seeds of Inga laurina led to the isolation of a new complex triterpenoid saponin, named ingasaponin. It is the first saponin isolated from a species of Inga genus. It was isolated by using chromatographic methods and its structural elucidation was performed using detailed analyses of (1)H and (13)C NMR spectra including 2D-NMR spectroscopic techniques and chemical conversions. Its structure was established as 21-[[(2E,6S)-6-[[6-deoxy-4-O-[(2E,6S)-6-[(ß-D-glucopyranosyl)oxy]-2,6-dimethyl-1-oxo-2,7-octadienyl]-[(ß-D-glucopyranosyl)oxy]-2,6-dimethyl-1-oxo-2,7-octadienyl]-[(ß-D-glucopyranosyl)oxy]-2,6-dimethyl-1-oxo-2,7-octadienyl]-[(ß-D-glucopyranosyl)oxy]-2-(hydroxymethyl)-6-methyl-1-oxo-2,7-octadienyl]oxy]-16-hydroxy-3-[[O-ß-D-xylopyranosyl-(1 â 2)-O-α-L-arabinopyranosyl-(1 â 6)-2-(acetylamino)-2-deoxy-ß-D-glucopyranosyl]oxy]-(3ß,16α,21ß)-olean-12-en-28-oic acid O-α-L-arabinofuranosyl-(1 â 4)-O-[ß-D-glucopyranosyl-(1 â 3)]-O-6-deoxy-α-L-mannopyranosyl-(1 â 2)-ß-D-glucopyranosyl ester (1). The hemolytic potential of 1 was evaluated using in vitro assays, and its adjuvant activity on the cellular immune response against ovalbumin antigen was investigated using in vivo models.